MOBILE VIEW  | 

LEVORPHANOL

Classification   |    Detailed evidence-based information

Therapeutic Toxic Class

    A) Levorphanol is a potent synthetic opioid analgesic similar to morphine.

Specific Substances

    1) Levorphan tartrate
    2) Levorphanol bitartrate
    3) Methorphinan tartrate
    4) CAS 77-07-6 (levorphanol)
    5) CAS 125-72-4 (anhydrous levorphanol tartrate)
    6) CAS 5985-38-6 (levorphanol tartrate dihydrate)
    1.2.1) MOLECULAR FORMULA
    1) C17-H23-NO.C4-H6-O6.2H2O (Prod Info Levorphanol tartrate oral tablets, 2008)

Available Forms Sources

    A) FORMS
    1) Levorphanol is available as 2 mg tablets for oral use (Prod Info Levorphanol tartrate oral tablets, 2008).
    B) USES
    1) Levorphanol is used for the management of moderate to severe pain (Prod Info Levorphanol tartrate oral tablets, 2008).

Life Support

    A) This overview assumes that basic life support measures have been instituted.

Clinical Effects

    0.2.1) SUMMARY OF EXPOSURE
    A) USES: Levorphanol is used for the management of moderate to severe pain. It is also subject to diversion and abuse for its euphoric effects.
    B) PHARMACOLOGY: Levorphanol is a potent synthetic mu-agonist opioid that exerts its action at receptors in the periventricular and periaqueductal gray matter in the brain and spinal cord, thus altering transmission and perception of pain. Levorphanol produces morphine-like analgesia but it is 4 to 8 times as potent as morphine and has a longer half-life.
    C) TOXICOLOGY: Therapeutic and toxic effects are mediated by different opioid receptors. Mu 1: Supraspinal and peripheral analgesia, sedation, and euphoria. Mu 2: Spinal analgesia, respiratory depression, physical dependence, GI dysmotility, bradycardia and pruritus. Kappa 1: Spinal analgesia and miosis. Kappa 2: Dysphoria and psychotomimesis. Kappa 3: Supraspinal analgesia. Chronic opioid users develop tolerance to the analgesic and euphoric effects, but not to the respiratory depression effects.
    D) EPIDEMIOLOGY: Overdose is uncommon, but can be life-threatening.
    E) WITH THERAPEUTIC USE
    1) The following adverse effects have been reported following levorphanol use: Lethargy, dizziness, confusion, nausea, vomiting, constipation, difficulty in urination, dry mouth, altered mood and mentation, pruritus, rash, urticaria, abdominal pain, diplopia, pupillary disorder, abnormal vision, seizures, amnesia, insomnia, coma, hypokinesia, dyskinesia, CNS stimulation, nervousness, depression, abnormal dreams, acute renal failure, hypotension, bradycardia, tachycardia, palpitations, extrasystoles, cardiac arrest, apnea, hypoventilation, and respiratory depression.
    F) WITH POISONING/EXPOSURE
    1) MILD TO MODERATE TOXICITY: Overdose effects are anticipated to be an extension of adverse effects observed following therapeutic doses. Lethargy, dizziness, confusion, nausea, vomiting, constipation, and pinpoint pupils may occur. Mild bradycardia or hypotension may be present.
    2) SEVERE TOXICITY: Respiratory depression may occur leading to apnea, hypoxia, extreme somnolence progressing to stupor and coma, bradycardia, and severe hypotension. Circulatory collapse, cardiac arrest and death may occur in severe overdoses.
    0.2.20) REPRODUCTIVE
    A) Levorphanol is classified by the manufacturer as FDA pregnancy category C. At the time of this review, no data were available to assess the teratogenic potential of this agent in humans.
    0.2.21) CARCINOGENICITY
    A) At the time of this review, no human data were available to assess the potential carcinogenic activity of levorphanol.

Laboratory Monitoring

    A) Monitor vital signs frequently, pulse oximetry, and continuous cardiac monitoring.
    B) Monitor for CNS and respiratory depression.
    C) Levorphanol plasma concentrations are not clinically useful or readily available. Urine toxicology screens may not detect synthetic opioids such as levorphanol, and are rarely useful in guiding therapy.
    D) Obtain acetaminophen and salicylate levels in patients with a self harm ingestion as other products may be involved.
    E) Other routine lab work is usually not indicated, unless it is helpful to rule out other causes or if the diagnosis of levorphanol toxicity is uncertain.
    F) Obtain a chest x-ray for persistent hypoxia. Consider a head CT or lumbar puncture, or both to rule out an intracranial mass, bleeding or infection, if the diagnosis is uncertain.

Treatment Overview

    0.4.2) ORAL/PARENTERAL EXPOSURE
    A) MANAGEMENT OF MILD TO MODERATE TOXICITY
    1) Patients may only need observation.
    B) MANAGEMENT OF SEVERE TOXICITY
    1) Administer oxygen and assist ventilation for respiratory depression. Naloxone is the antidote indicated for severe toxicity (respiratory or CNS depression). Orotracheal intubation for airway protection should be performed early in cases of obtundation and/or respiratory depression that do not respond to naloxone, or in patients who develop severe acute lung injury.
    C) DECONTAMINATION
    1) PREHOSPITAL: Do not administer activated charcoal because of the risk of CNS depression or seizures and subsequent aspiration.
    2) HOSPITAL: Consider activated charcoal if a patient presents soon after an ingestion and is not manifesting signs and symptoms of toxicity. Activated charcoal is generally not recommended in patients with significant signs of toxicity because of the risk of aspiration. Gastric lavage is not recommended as patients usually do well with supportive care.
    D) AIRWAY MANAGEMENT
    1) Administer oxygen and assist ventilation for respiratory depression. Orotracheal intubation for airway protection should be performed early in cases of obtundation and/or respiratory depression that do not respond to naloxone, or in patients who develop severe acute lung injury.
    E) ANTIDOTE
    1) NALOXONE, an opioid antagonist, is the specific antidote. Naloxone can be given intravascularly, intramuscularly, subcutaneously, intranasally or endotracheally. The usual dose is 0.4 to 2.0 mg IV. In patients with suspected opioid dependence incremental doses of 0.2 mg IV should be administered, titrated to reversal of respiratory depression and coma, to avoid precipitating acute opioid withdrawal. Doses may be repeated every 2 to 3 minutes up to 20 mg. Very high doses are rarely needed, but may occasionally be necessary. A CONTINUOUS infusion may be necessary in patients that have ingested a large overdose. A suggested starting rate is two-thirds of the dose effective for initial reversal that is administered each hour; titrate as needed. DURATION of effect is usually 1 to 2 hours. Levorphanol has a longer duration of effect, so it is necessary to observe the patient at least 3 to 4 hours after the last dose of naloxone to ensure that the patient does not have recurrent symptoms of toxicity. Naloxone can precipitate withdrawal in an opioid-dependent patients, which is usually not life-threatening; however it can be extremely uncomfortable for the patient.
    F) SEIZURE
    1) Seizures are rare, but may be a result of hypoxia. Treatment includes ensuring adequate oxygenation, and administering intravenous benzodiazepines; propofol or barbiturates may be indicated, if seizures persist.
    G) ACUTE LUNG INJURY
    1) Acute lung injury can develop in a small proportion of patients after an acute opioid overdose. The pathophysiology is unclear. Patients should be observed for 4 to 6 hours after overdose to evaluate for hypoxia and/or the development of acute lung injury.
    H) HYPOTENSION
    1) Hypotension is often reversed by naloxone. Initially, treat with a saline bolus, if patient can tolerate a fluid load, then adrenergic vasopressors to raise mean arterial pressure.
    I) ENHANCED ELIMINATION
    1) Hemodialysis and hemoperfusion are not of value because of the large volume of distribution.
    J) PATIENT DISPOSITION
    1) HOME CRITERIA: Respiratory depression may occur at doses just above the therapeutic dose. Children with inadvertent ingestions should be observed and evaluated in the hospital as they are generally opioid naive and may develop respiratory depression. Adults should be evaluated by a health care professional if they have received a higher than recommended (therapeutic) dose, especially if opioid naive.
    2) OBSERVATION CRITERIA: Symptomatic patients, those with deliberate ingestions, adults who have ingested more than a therapeutic dose, and any pediatric ingestions, should be sent to a health care facility for observation for at least 4 hours, to ensure that peak plasma levels have been reached and there has been sufficient time for symptoms to develop. Patients who are treated with naloxone should be observed for 4 to 6 hours after the last dose, for recurrent CNS depression or acute lung injury.
    3) ADMISSION CRITERIA: Patients with significant, persistent central nervous system depression or seizures should be admitted to the hospital. A patient needing more than 2 doses of naloxone should be admitted; additional doses may be needed. Patients with coma, seizures, dysrhythmias, delirium, and those needing a naloxone infusion or who are intubated should be admitted to an intensive care setting.
    4) CONSULT CRITERIA: Consult a poison center or medical toxicologist for assistance in managing patients with severe toxicity or in whom the diagnosis is not clear.
    K) PITFALLS
    1) Patients may be discharged prematurely after mental status clears with a dose of naloxone. Naloxone's duration of effect is much shorter than the duration of effect for levorphanol. Other causes of altered mental status must be ruled out, such as hypoxia or hypoglycemia.
    L) PHARMACOKINETICS
    1) Extensively metabolized in the liver; clearance 0.75 to 1.1 L/kg/hr. Protein binding 40%; Half-life 11 to 16 hours, volume of distribution 10 to 13 L/kg.
    M) TOXICOKINETICS
    1) Opioids slow GI motility, which may lead to prolonged absorption.
    N) DIFFERENTIAL DIAGNOSIS
    1) Overdose with other sedating agents (eg, ethanol, benzodiazepine/barbiturate, antipsychotics, other opioids); overdose with central alpha 2 agonists (eg, clonidine, tizanidine, imidazoline decongestants); CNS infection; intracranial hemorrhage; hypoglycemia or hypoxia.
    O) PREDISPOSING CONDITIONS
    1) Patients with renal failure may develop cumulative toxicity at therapeutic doses due to decreased elimination.
    P) DRUG INTERACTIONS
    1) Coingestion of other CNS depressant drugs (eg, benzodiazepines, barbiturates, ethanol) will increase the CNS and respiratory depressant effects.

Range Of Toxicity

    A) TOXICITY: The toxic dose is not established and depends on individual patient tolerance.
    B) THERAPEUTIC DOSE: 2 mg orally, may repeat in 6 to 8 hr as needed; may increase dose up to 3 mg every 6 to 8 hr if needed; MAX 6 to 12 mg daily. CHRONIC PAIN: Levorphanol produces morphine-like analgesia but it is 4 to 8 times as potent as morphine and has a longer half-life. DOSE: initial, total daily dose 1/15 to 1/12 of total daily dose of oral morphine; wait 72 hours between dose adjustments. CHILDREN: Safety and effectiveness in pediatric patients have not been established.

Summary Of Exposure

    A) USES: Levorphanol is used for the management of moderate to severe pain. It is also subject to diversion and abuse for its euphoric effects.
    B) PHARMACOLOGY: Levorphanol is a potent synthetic mu-agonist opioid that exerts its action at receptors in the periventricular and periaqueductal gray matter in the brain and spinal cord, thus altering transmission and perception of pain. Levorphanol produces morphine-like analgesia but it is 4 to 8 times as potent as morphine and has a longer half-life.
    C) TOXICOLOGY: Therapeutic and toxic effects are mediated by different opioid receptors. Mu 1: Supraspinal and peripheral analgesia, sedation, and euphoria. Mu 2: Spinal analgesia, respiratory depression, physical dependence, GI dysmotility, bradycardia and pruritus. Kappa 1: Spinal analgesia and miosis. Kappa 2: Dysphoria and psychotomimesis. Kappa 3: Supraspinal analgesia. Chronic opioid users develop tolerance to the analgesic and euphoric effects, but not to the respiratory depression effects.
    D) EPIDEMIOLOGY: Overdose is uncommon, but can be life-threatening.
    E) WITH THERAPEUTIC USE
    1) The following adverse effects have been reported following levorphanol use: Lethargy, dizziness, confusion, nausea, vomiting, constipation, difficulty in urination, dry mouth, altered mood and mentation, pruritus, rash, urticaria, abdominal pain, diplopia, pupillary disorder, abnormal vision, seizures, amnesia, insomnia, coma, hypokinesia, dyskinesia, CNS stimulation, nervousness, depression, abnormal dreams, acute renal failure, hypotension, bradycardia, tachycardia, palpitations, extrasystoles, cardiac arrest, apnea, hypoventilation, and respiratory depression.
    F) WITH POISONING/EXPOSURE
    1) MILD TO MODERATE TOXICITY: Overdose effects are anticipated to be an extension of adverse effects observed following therapeutic doses. Lethargy, dizziness, confusion, nausea, vomiting, constipation, and pinpoint pupils may occur. Mild bradycardia or hypotension may be present.
    2) SEVERE TOXICITY: Respiratory depression may occur leading to apnea, hypoxia, extreme somnolence progressing to stupor and coma, bradycardia, and severe hypotension. Circulatory collapse, cardiac arrest and death may occur in severe overdoses.

Heent

    3.4.3) EYES
    A) WITH THERAPEUTIC USE
    1) DIPLOPIA: Diplopia has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    2) ABNORMAL VISION: Abnormal vision has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).

Cardiovascular

    3.5.2) CLINICAL EFFECTS
    A) HYPOTENSIVE EPISODE
    1) WITH THERAPEUTIC USE
    a) Hypotension has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    2) WITH POISONING/EXPOSURE
    a) Hypotension may occur following levorphanol overdose (Prod Info Levorphanol tartrate oral tablets, 2008).
    B) CONDUCTION DISORDER OF THE HEART
    1) WITH THERAPEUTIC USE
    a) Dysrhythmias, including bradycardia and tachycardia, and extrasystoles have been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    2) WITH POISONING/EXPOSURE
    a) Bradycardia may occur following levorphanol overdose (Prod Info Levorphanol tartrate oral tablets, 2008).
    C) PALPITATIONS
    1) WITH THERAPEUTIC USE
    a) Palpitations have been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).

Neurologic

    3.7.2) CLINICAL EFFECTS
    A) DIZZINESS
    1) WITH THERAPEUTIC USE
    a) Dizziness has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    B) LETHARGY
    1) WITH THERAPEUTIC USE
    a) Lethargy has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    C) CLOUDED CONSCIOUSNESS
    1) WITH THERAPEUTIC USE
    a) Confusion has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    D) ALTERED MENTAL STATUS
    1) WITH THERAPEUTIC USE
    a) Mental state alterations, which are dose-related in their frequency and intensity, have been reported with the use levorphanol and are typical of opioid adverse effects (Prod Info Levorphanol tartrate oral tablets, 2008).
    E) AMNESIA
    1) WITH THERAPEUTIC USE
    a) Amnesia has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    F) INSOMNIA
    1) WITH THERAPEUTIC USE
    a) Insomnia has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    G) SEIZURE
    1) WITH THERAPEUTIC USE
    a) Seizures have been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    H) COMA
    1) WITH POISONING/EXPOSURE
    a) Extreme somnolence progressing to stupor and coma may occur in severe overdoses (Prod Info Levorphanol tartrate oral tablets, 2008).
    I) BEHAVIOR SHOWING REDUCED MOTOR ACTIVITY
    1) WITH THERAPEUTIC USE
    a) Hypokinesia has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    J) DYSKINESIA
    1) WITH THERAPEUTIC USE
    a) Dyskinesia has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    K) HYPERACTIVE BEHAVIOR
    1) WITH THERAPEUTIC USE
    a) Hyperkinesia has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    L) CENTRAL NERVOUS SYSTEM STIMULATION
    1) WITH THERAPEUTIC USE
    a) CNS stimulation has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    M) FEELING NERVOUS
    1) WITH THERAPEUTIC USE
    a) Nervousness has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).

Gastrointestinal

    3.8.2) CLINICAL EFFECTS
    A) NAUSEA
    1) WITH THERAPEUTIC USE
    a) Nausea, which is dose-related in its frequency and intensity, has been reported with the use levorphanol and is typical of opioid adverse effects (Prod Info Levorphanol tartrate oral tablets, 2008).
    B) VOMITING
    1) WITH THERAPEUTIC USE
    a) Vomiting, which is dose-related in its frequency and intensity, has been reported with the use levorphanol and is typical of opioid adverse effects (Prod Info Levorphanol tartrate oral tablets, 2008).
    C) CONSTIPATION
    1) WITH THERAPEUTIC USE
    a) Constipation, which is dose-related in its frequency and intensity, has been reported with the use levorphanol and is typical of opioid adverse effects (Prod Info Levorphanol tartrate oral tablets, 2008).
    D) INDIGESTION
    1) WITH THERAPEUTIC USE
    a) Dyspepsia has been reported with the use levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    E) APTYALISM
    1) WITH THERAPEUTIC USE
    a) Dry mouth has been reported with the use levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    F) ABDOMINAL PAIN
    1) WITH THERAPEUTIC USE
    a) Abdominal pain has been reported with the use levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).

Genitourinary

    3.10.2) CLINICAL EFFECTS
    A) DIFFICULTY PASSING URINE
    1) WITH THERAPEUTIC USE
    a) Difficulty in urination, which is dose-related in its frequency and intensity, has been reported with the use levorphanol and is typical of opioid adverse effects(Prod Info Levorphanol tartrate oral tablets, 2008).
    B) RENAL FAILURE SYNDROME
    1) WITH THERAPEUTIC USE
    a) Renal failure has been reported with the use levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).

Dermatologic

    3.14.2) CLINICAL EFFECTS
    A) ITCHING OF SKIN
    1) WITH THERAPEUTIC USE
    a) Pruritus, which is dose-related in its frequency and intensity, has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    B) ERUPTION
    1) WITH THERAPEUTIC USE
    a) Skin rash has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    C) URTICARIA
    1) WITH THERAPEUTIC USE
    a) Urticaria has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    D) INJECTION SITE REACTION
    1) WITH THERAPEUTIC USE
    a) Injection site reactions have been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    E) SWEATING
    1) WITH THERAPEUTIC USE
    a) Sweating has been reported with the use of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    F) FLUSHING
    1) WITH THERAPEUTIC USE
    a) Flushing, which is dose-related in its frequency and intensity, has been reported with the use levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).

Reproductive

    3.20.1) SUMMARY
    A) Levorphanol is classified by the manufacturer as FDA pregnancy category C. At the time of this review, no data were available to assess the teratogenic potential of this agent in humans.
    3.20.2) TERATOGENICITY
    A) LACK OF INFORMATION
    1) At the time of this review, no data were available to assess the teratogenic potential of this agent in humans.
    B) ANIMAL STUDIES
    1) In an animal study, levorphanol was teratogenic in mice given a single oral dose of 25 mg/kg (Prod Info Levorphanol tartrate oral tablets, 2008).
    2) Approximately 50% mortality rate was observed in mouse embryos when given a single oral dose of 25 mg/kg (Prod Info Levorphanol tartrate oral tablets, 2008).
    3.20.3) EFFECTS IN PREGNANCY
    A) PREGNANCY CATEGORY
    1) Levorphanol is classified by the manufacturer as FDA pregnancy category C (Prod Info Levorphanol tartrate oral tablets, 2008).
    B) PHYSICAL DEPENDENCE
    1) Physical dependence may occur in infants born to mothers who have been taking opioids regularly before the delivery (Prod Info Levorphanol tartrate oral tablets, 2008).
    C) WITHDRAWAL SYNDROME
    1) Withdrawal symptoms have been observed in neonates whose mothers were taking narcotic analgesics during pregnancy. Symptoms of withdrawal may include irritability, hyperreflexia, hyperactivity, tremors, abnormal crying, diaphoresis, fever, vomiting, sneezing, yawning, and tachypnea (Blinick et al, 1973).
    D) ANIMAL STUDIES
    1) In one rabbit study, levorphanol (1.5 to 20 mg/kg IV) crossed the placental barrier and depressed fetal respiration (Prod Info Levorphanol tartrate oral tablets, 2008).
    3.20.4) EFFECTS DURING BREAST-FEEDING
    A) BREAST MILK
    1) It is not known if levorphanol is excreted in human breast milk. However, morphine, which is structurally similar to levorphanol, has been shown to be excreted in human breast milk at a milk to plasma morphine ratio of approximately 2.5 to 1. The nursing infant may experience withdrawal symptoms when maternal morphine therapy is discontinued. Because of the potential for adverse events in the nursing infant, a decision should be made whether to discontinue nursing or discontinue levorphanol, taking into account the benefit of the drug to the mother (Prod Info EMBEDA(R) oral extended-release capsules, 2009; Prod Info Levorphanol tartrate oral tablets, 2008).
    3.20.5) FERTILITY
    A) ANIMAL STUDIES
    1) At the time of this review, studies have not been done on levorphanol to evaluate its effect on fertility (Prod Info Levorphanol tartrate oral tablets, 2008).

Carcinogenicity

    3.21.2) SUMMARY/HUMAN
    A) At the time of this review, no human data were available to assess the potential carcinogenic activity of levorphanol.
    3.21.3) HUMAN STUDIES
    A) LACK OF INFORMATION
    1) At the time of this review, no human data were available to assess the potential carcinogenic activity of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    3.21.4) ANIMAL STUDIES
    A) LACK OF INFORMATION
    1) At the time of this review, no animal data were available to assess the potential carcinogenic activity of levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).

Respiratory

    3.6.2) CLINICAL EFFECTS
    A) DECREASED RESPIRATORY FUNCTION
    1) WITH THERAPEUTIC USE
    a) Respiratory depression is a potential adverse effect of levorphanol that can be serious or fatal. Vulnerable patients include those with already impaired respiratory reserve or with respiratory depression from another source, such as other medications, severe infections, restrictive respiratory diseases, uremia, chronic bronchial asthma, intrapulmonary shunting, or obstructive respiratory conditions (Prod Info Levorphanol tartrate oral tablets, 2008).
    b) The respiratory depressant effects of levorphanol may be increased in patients with preexisting elevations in intracranial pressure, intracranial lesions, or head injuries. Other adverse effects of opioids like levorphanol may mask the clinical course of head injuries or complicate neurological diagnoses due to its effects on level of consciousness(Prod Info Levorphanol tartrate oral tablets, 2008).
    2) WITH POISONING/EXPOSURE
    a) Following a severe overdose, respiratory depression may occur leading to apnea, hypoxia, extreme somnolence progressing to stupor and coma, bradycardia, and severe hypotension (Prod Info Levorphanol tartrate oral tablets, 2008).
    B) HYPOVENTILATION
    1) WITH THERAPEUTIC USE
    a) Hypoventilation has been reported with the use levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).
    C) APNEA
    1) WITH THERAPEUTIC USE
    a) Apnea has been reported with the use levorphanol (Prod Info Levorphanol tartrate oral tablets, 2008).

Monitoring Parameters Levels

    4.1.1) SUMMARY
    A) Monitor vital signs frequently, pulse oximetry, and continuous cardiac monitoring.
    B) Monitor for CNS and respiratory depression.
    C) Levorphanol plasma concentrations are not clinically useful or readily available. Urine toxicology screens may not detect synthetic opioids such as levorphanol, and are rarely useful in guiding therapy.
    D) Obtain acetaminophen and salicylate levels in patients with a self harm ingestion as other products may be involved.
    E) Other routine lab work is usually not indicated, unless it is helpful to rule out other causes or if the diagnosis of levorphanol toxicity is uncertain.
    F) Obtain a chest x-ray for persistent hypoxia. Consider a head CT or lumbar puncture, or both to rule out an intracranial mass, bleeding or infection, if the diagnosis is uncertain.

Life Support

    A) Support respiratory and cardiovascular function.

Patient Disposition

    6.3.1) DISPOSITION/ORAL EXPOSURE
    6.3.1.1) ADMISSION CRITERIA/ORAL
    A) Patients with significant, persistent central nervous system depression or seizures should be admitted to the hospital. A patient needing more than 2 doses of naloxone should be admitted; additional doses may be needed. Patients with coma, seizures, dysrhythmias, delirium, and those needing a naloxone infusion or who are intubated should be admitted to an intensive care setting.
    6.3.1.2) HOME CRITERIA/ORAL
    A) Respiratory depression may occur at doses just above the therapeutic dose. Children with inadvertent ingestions should be observed and evaluated in the hospital as they are generally opioid naive and may develop respiratory depression. Adults should be evaluated by a health care professional if they have received a higher than recommended (therapeutic) dose, especially if opioid naive.
    6.3.1.3) CONSULT CRITERIA/ORAL
    A) Consult a poison center or medical toxicologist for assistance in managing patients with severe toxicity or in whom the diagnosis is not clear.
    6.3.1.5) OBSERVATION CRITERIA/ORAL
    A) Symptomatic patients, those with deliberate ingestions, adults who have ingested more than a therapeutic dose, and any pediatric ingestions should be sent to a health care facility for observation for at least 4 hours, to ensure that peak plasma levels have been reached and there has been sufficient time for symptoms to develop. Patients who are treated with naloxone should be observed for 4 to 6 hours after the last dose, for recurrent CNS depression or acute lung injury.

Monitoring

    A) Monitor vital signs frequently, pulse oximetry, and continuous cardiac monitoring.
    B) Monitor for CNS and respiratory depression.
    C) Levorphanol plasma concentrations are not clinically useful or readily available. Urine toxicology screens may not detect synthetic opioids such as levorphanol, and are rarely useful in guiding therapy.
    D) Obtain acetaminophen and salicylate levels in patients with a self harm ingestion as other products may be involved.
    E) Other routine lab work is usually not indicated, unless it is helpful to rule out other causes or if the diagnosis of levorphanol toxicity is uncertain.
    F) Obtain a chest x-ray for persistent hypoxia. Consider a head CT or lumbar puncture, or both to rule out an intracranial mass, bleeding or infection, if the diagnosis is uncertain.

Oral Exposure

    6.5.1) PREVENTION OF ABSORPTION/PREHOSPITAL
    A) PREHOSPITAL: Do not administer activated charcoal because of the risk of CNS depression or seizures and subsequent aspiration.
    B) NALOXONE/SUMMARY
    1) Naloxone, a pure opioid antagonist, reverses coma and respiratory depression from all opioids. It has no agonist effects and can safely be employed in a mixed or unknown overdose where it can be diagnostic and therapeutic without risk to the patient.
    2) Indicated in patients with mental status and respiratory depression possibly related to opioid overdose (Hoffman et al, 1991).
    3) DOSE: The initial dose of naloxone should be low (0.04 to 0.4 mg) with a repeat dosing as needed or dose escalation to 2 mg as indicated due to the risk of opioid withdrawal in an opioid-tolerant individual; if delay in obtaining venous access, may administer subcutaneously, intramuscularly, intranasally, via nebulizer (in a patient with spontaneous respirations) or via an endotracheal tube (Vanden Hoek,TL,et al).
    4) Recurrence of opioid toxicity has been reported to occur in approximately 1 out of 3 adult ED opioid overdose cases after a response to naloxone. Recurrences are more likely with long-acting opioids (Watson et al, 1998)
    C) NALOXONE DOSE/ADULT
    1) INITIAL BOLUS DOSE: Because naloxone can produce opioid withdrawal in an opioid-dependent individual leading to severe agitation and hypertension, the initial dose of naloxone should be low (0.04 to 0.4 mg) with a repeat dosing as needed or dose escalation to 2 mg as indicated (Vanden Hoek,TL,et al).
    a) This dose can also be given intramuscularly or subcutaneously in the absence of intravenous access (Howland & Nelson, 2011; Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008; Maio et al, 1987; Wanger et al, 1998).
    2) Larger doses may be needed to reverse opioid effects. Generally, if no response is observed after 8 to 10 milligrams has been administered, the diagnosis of opioid-induced respiratory depression should be questioned (Howland & Nelson, 2011; Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008). Very large doses of naloxone (10 milligrams or more) may be required to reverse the effects of a buprenorphine overdose (Gal, 1989; Jasinski et al, 1978).
    a) Single doses of up to 24 milligrams have been given without adverse effect (Evans et al, 1973).
    3) REPEAT DOSE: The effective naloxone dose may have to be repeated every 20 to 90 minutes due to the much longer duration of action of the opioid agonist used(Howland & Nelson, 2011).
    a) OPIOID DEPENDENT PATIENTS: The goal of naloxone therapy is to reverse respiratory depression without precipitating significant withdrawal. Starting doses of naloxone 0.04 mg IV, or 0.001 mg/kg, have been suggested as appropriate for opioid-dependent patients without severe respiratory depression (Howland & Nelson, 2011). If necessary the dose may be repeated or increased gradually until the desired response is achieved (adequate respirations, ability to protect airway, responds to stimulation but no evidence of withdrawal) (Howland & Nelson, 2011). In the presence of opioid dependence, withdrawal symptoms typically appear within minutes of naloxone administration and subside in about 2 hours. The severity and duration of the withdrawal syndrome are dependant upon the naloxone dose and the degree and type of dependence.(Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008)
    b) PRECAUTION should be taken in the presence of a mixed overdose of a sympathomimetic with an opioid. Administration of naloxone may provoke serious sympathomimetic toxicity by removing the protective opioid-mediated CNS depressant effects. Arrhythmogenic effects of naloxone may also be potentiated in the presence of severe hyperkalemia (McCann et al, 2002).
    4) NALOXONE DOSE/CHILDREN
    a) LESS THAN 5 YEARS OF AGE OR LESS THAN 20 KG: 0.1 mg/kg IV/intraosseous/IM/subcutaneously maximum dose 2 mg; may repeat dose every 2 to 5 minutes until symptoms improve (Kleinman et al, 2010; Hegenbarth & American Academy of Pediatrics Committee on Drugs, 2008)
    b) 5 YEARS OF AGE OR OLDER OR GREATER THAN 20 KG: 2 mg IV/intraosseous/IM/subcutaneouslymay repeat dose every 2 to 5 minutes until symptoms improve (Kleinman et al, 2010; Hegenbarth & American Academy of Pediatrics Committee on Drugs, 2008; Krauss & Green, 2006). Although naloxone may be given via the endotracheal tube for pediatric resuscitation, optimal doses are unknown. Some experts have recommended using 2 to 3 times the IV dose (Kleinman et al, 2010)
    c) AVOIDANCE OF OPIOID WITHDRAWAL: In cases of known or suspected chronic opioid therapy, a lower dose of 0.01 mg/kg may be considered and titrated to effect to avoid withdrawal: INITIAL DOSE: 0.01 mg/kg body weight given IV. If this does not result in clinical improvement, an additional dose of 0.1 mg/kg body weight may be given. It may be given by the IM or subQ route if the IV route is not available (Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008)
    5) NALOXONE DOSE/NEONATE
    a) The American Academy of Pediatrics recommends a neonatal dose of 0.1 mg/kg IV or intratracheally from birth until age 5 years or 20 kilograms of body weight (AAP, 1989; Kleinman et al, 2010).
    b) Smaller doses (10 to 30 mcg/kg IV) have been successful in the setting of exposure via maternal administration of narcotics or administration to neonates in therapeutic doses for anesthesia (Wiener et al, 1977; Welles et al, 1984; Fischer & Cook, 1974; Brice et al, 1979).
    c) POTENTIAL OF WITHDRAWAL: The risk of precipitating withdrawal in an addicted neonate should be considered. Withdrawal seizures have been provoked in infants from opioid-abusing mothers when the infants were given naloxone at birth to stimulate breathing (Gibbs et al, 1989).
    d) In cases of inadvertent administration of an opioid overdose to a neonate, larger doses may be required. In one case of oral morphine intoxication, 0.16 milligram/kilogram/hour was required for 5 days (Tenenbein, 1984).
    6) NALOXONE/ALTERNATE ROUTES
    a) If intravenous access cannot be rapidly established, naloxone can be administered via subcutaneous or intramuscular injection, intranasally, or via inhaled nebulization in patients with spontaneous respirations.
    b) INTRAMUSCULAR/SUBCUTANEOUS ROUTES: If an intravenous line cannot be secured due to hypoperfusion or lack of adequate veins then naloxone can be administered by other routes.
    c) The intramuscular or subcutaneous routes are effective if hypoperfusion is not present (Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008). The delay required to establish an IV, offsets the slower rate of subcutaneous absorption (Wanger et al, 1998).
    d) Naloxone Evzio(TM) is a hand-held autoinjector intended for the emergency treatment of known or suspected opioid overdose. The autoinjector is equipped with an electronic voice instruction system to assist caregivers with administration. It is available as 0.4 mg/0.4 mL solution for injection in a pre-filled auto-injector (Prod Info EVZIO(TM) injection solution, 2014).
    e) INTRANASAL ROUTE: Intranasal naloxone has been shown to be effective in opioid overdose; bioavailability appears similar to the intravenous route (Kelly & Koutsogiannis, 2002). Based on several case series of patients with suspected opiate overdose, the average response time of 3.4 minutes was observed using a formulation of 1 mg/mL/nostril by a mucosal atomization device (Kerr et al, 2009; Kelly & Koutsogiannis, 2002). However, a young adult who intentionally masticated two 25 mcg fentanyl patches and developed agonal respirations (6 breaths per minute), decreased mental status and mitotic pupils did not respond to intranasal naloxone (1 mg in each nostril) administered by paramedics. After 11 minutes, paramedics placed an IV and administered 1 mg of IV naloxone; respirations normalized and mental status improved. Upon admission, 2 additional doses of naloxone 0.4 mg IV were needed. The patient was monitored overnight and discharged the following day without sequelae. Its suggested that intranasal administration can lead to unpredictable absorption (Zuckerman et al, 2014).
    1) Narcan(R) nasal spray is supplied as a single 4 mg dose of naloxone hydrochloride in a 0.1 mL intranasal spray (Prod Info NARCAN(R) nasal spray, 2015).
    2) FDA DOSING: Initial dose: 1 spray (4 mg) intranasally into 1 nostril. Subsequent doses: Use a new Narcan(R) nasal spray and administer into alternating nostrils. May repeat dose every 2 to 3 minutes. Requirement for repeat dosing is dependent on the amount, type, and route of administration of the opioid being antagonized. Higher or repeat doses may be required for partial agonists or mixed agonist/antagonists (Prod Info NARCAN(R) nasal spray, 2015).
    3) AMERICAN HEART ASSOCIATION GUIDELINE DOSING: Usual dose: 2 mg intranasally as soon as possible; may repeat after 4 minutes (Lavonas et al, 2015). Higher doses may be required with atypical opioids (VandenHoek et al, 2010).
    4) ABSORPTION: Based on limited data, the absorption rate of intranasal administration is comparable to intravenous administration. The peak plasma concentration of intranasal administration is estimated to be 3 minutes which is similar to the intravenous route (Kerr et al, 2009). In rare cases, nasal absorption may be inhibited by injury, prior use of intranasal drugs, or excessive secretions (Kerr et al, 2009).
    f) NEBULIZED ROUTE: DOSE: A suggested dose is 2 mg naloxone with 3 mL of normal saline for suspected opioid overdose in patients with some spontaneous respirations (Weber et al, 2012).
    g) ENDOTRACHEAL ROUTE: Endotracheal administration of naloxone can be effective(Tandberg & Abercrombie, 1982), optimum dose unknown but 2 to 3 times the intravenous dose had been recommended by some (Kleinman et al, 2010).
    7) NALOXONE/CONTINUOUS INFUSION METHOD
    a) A continuous infusion of naloxone may be employed in circumstances of opioid overdose with long acting opioids (Howland & Nelson, 2011; Redfern, 1983).
    b) The patient is given an initial dose of IV naloxone to achieve reversal of opioid effects and is then started on a continuous infusion to maintain this state of antagonism.
    c) DOSE: Utilize two-thirds of the initial naloxone bolus on an hourly basis (Howland & Nelson, 2011; Mofenson & Caraccio, 1987). For an adult, prepare the dose by multiplying the effective bolus dose by 6.6, and add that amount to 1000 mL and administer at an IV infusion rate of 100 mL/hour (Howland & Nelson, 2011).
    d) Dose and duration of action of naloxone therapy varies based on several factors; continuous monitoring should be used to prevent withdrawal induction (Howland & Nelson, 2011).
    e) Observe patients for evidence of CNS or respiratory depression for at least 2 hours after discontinuing the infusion (Howland & Nelson, 2011).
    8) NALOXONE/PREGNANCY
    a) In general, the smallest dose of naloxone required to reverse life threatening opioid effects should be used in pregnant women. Naloxone detoxification of opioid addicts during pregnancy may result in fetal distress, meconium staining and fetal death (Zuspan et al, 1975). When naloxone is used during pregnancy, opioid abstinence may be provoked in utero (Umans & Szeto, 1985).
    6.5.2) PREVENTION OF ABSORPTION
    A) SUMMARY: Consider activated charcoal if a patient presents soon after an ingestion and is not manifesting signs and symptoms of toxicity. Activated charcoal is generally not recommended in patients with significant signs of toxicity because of the risk of aspiration. Gastric lavage is not recommended as patients usually do well with supportive care.
    B) CHARCOAL ADMINISTRATION
    1) Consider administration of activated charcoal after a potentially toxic ingestion (Chyka et al, 2005). Administer charcoal as an aqueous slurry; most effective when administered within one hour of ingestion.
    C) CHARCOAL DOSE
    1) Use a minimum of 240 milliliters of water per 30 grams charcoal (FDA, 1985). Optimum dose not established; usual dose is 25 to 100 grams in adults and adolescents; 25 to 50 grams in children aged 1 to 12 years (or 0.5 to 1 gram/kilogram body weight) ; and 0.5 to 1 gram/kilogram in infants up to 1 year old (Chyka et al, 2005).
    a) Routine use of a cathartic with activated charcoal is NOT recommended as there is no evidence that cathartics reduce drug absorption and cathartics are known to cause adverse effects such as nausea, vomiting, abdominal cramps, electrolyte imbalances and occasionally hypotension (None Listed, 2004).
    2) ADVERSE EFFECTS/CONTRAINDICATIONS
    a) Complications: emesis, aspiration (Chyka et al, 2005). Aspiration may be complicated by acute respiratory failure, ARDS, bronchiolitis obliterans or chronic lung disease (Golej et al, 2001; Graff et al, 2002; Pollack et al, 1981; Harris & Filandrinos, 1993; Elliot et al, 1989; Rau et al, 1988; Golej et al, 2001; Graff et al, 2002). Refer to the ACTIVATED CHARCOAL/TREATMENT management for further information.
    b) Contraindications: unprotected airway (increases risk/severity of aspiration) , nonfunctioning gastrointestinal tract, uncontrolled vomiting, and ingestion of most hydrocarbons (Chyka et al, 2005).
    6.5.3) TREATMENT
    A) MONITORING OF PATIENT
    1) Monitor vital signs frequently, pulse oximetry, and continuous cardiac monitoring.
    2) Monitor for CNS and respiratory depression.
    3) Levorphanol plasma concentrations are not clinically useful or readily available. Urine toxicology screens may not detect synthetic opioids such as levorphanol, and are rarely useful in guiding therapy.
    4) Obtain acetaminophen and salicylate levels and serum electrolytes in patients with a self harm ingestion as other products may be involved.
    5) Other routine lab work is usually not indicated, unless it is helpful to rule out other causes or if the diagnosis of levorphanol toxicity is uncertain.
    6) Obtain a chest x-ray for persistent hypoxia. Consider a head CT or lumbar puncture, or both to rule out an intracranial mass, bleeding or infection, if the diagnosis is uncertain.
    B) AIRWAY MANAGEMENT
    1) Administer oxygen and assist ventilation for respiratory depression. Orotracheal intubation for airway protection should be performed early in cases of obtundation and/or respiratory depression that do not respond to naloxone, or in patients who develop severe acute lung injury.
    C) NALOXONE
    1) NALOXONE/SUMMARY
    a) Naloxone, a pure opioid antagonist, reverses coma and respiratory depression from all opioids. It has no agonist effects and can safely be employed in a mixed or unknown overdose where it can be diagnostic and therapeutic without risk to the patient.
    b) Indicated in patients with mental status and respiratory depression possibly related to opioid overdose (Hoffman et al, 1991).
    c) DOSE: The initial dose of naloxone should be low (0.04 to 0.4 mg) with a repeat dosing as needed or dose escalation to 2 mg as indicated due to the risk of opioid withdrawal in an opioid-tolerant individual; if delay in obtaining venous access, may administer subcutaneously, intramuscularly, intranasally, via nebulizer (in a patient with spontaneous respirations) or via an endotracheal tube (Vanden Hoek,TL,et al).
    d) Recurrence of opioid toxicity has been reported to occur in approximately 1 out of 3 adult ED opioid overdose cases after a response to naloxone. Recurrences are more likely with long-acting opioids (Watson et al, 1998)
    2) NALOXONE DOSE/ADULT
    a) INITIAL BOLUS DOSE: Because naloxone can produce opioid withdrawal in an opioid-dependent individual leading to severe agitation and hypertension, the initial dose of naloxone should be low (0.04 to 0.4 mg) with a repeat dosing as needed or dose escalation to 2 mg as indicated (Vanden Hoek,TL,et al).
    1) This dose can also be given intramuscularly or subcutaneously in the absence of intravenous access (Howland & Nelson, 2011; Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008; Maio et al, 1987; Wanger et al, 1998).
    b) Larger doses may be needed to reverse opioid effects. Generally, if no response is observed after 8 to 10 milligrams has been administered, the diagnosis of opioid-induced respiratory depression should be questioned (Howland & Nelson, 2011; Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008). Very large doses of naloxone (10 milligrams or more) may be required to reverse the effects of a buprenorphine overdose (Gal, 1989; Jasinski et al, 1978).
    1) Single doses of up to 24 milligrams have been given without adverse effect (Evans et al, 1973).
    c) REPEAT DOSE: The effective naloxone dose may have to be repeated every 20 to 90 minutes due to the much longer duration of action of the opioid agonist used(Howland & Nelson, 2011).
    1) OPIOID DEPENDENT PATIENTS: The goal of naloxone therapy is to reverse respiratory depression without precipitating significant withdrawal. Starting doses of naloxone 0.04 mg IV, or 0.001 mg/kg, have been suggested as appropriate for opioid-dependent patients without severe respiratory depression (Howland & Nelson, 2011). If necessary the dose may be repeated or increased gradually until the desired response is achieved (adequate respirations, ability to protect airway, responds to stimulation but no evidence of withdrawal) (Howland & Nelson, 2011). In the presence of opioid dependence, withdrawal symptoms typically appear within minutes of naloxone administration and subside in about 2 hours. The severity and duration of the withdrawal syndrome are dependant upon the naloxone dose and the degree and type of dependence.(Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008)
    2) PRECAUTION should be taken in the presence of a mixed overdose of a sympathomimetic with an opioid. Administration of naloxone may provoke serious sympathomimetic toxicity by removing the protective opioid-mediated CNS depressant effects. Arrhythmogenic effects of naloxone may also be potentiated in the presence of severe hyperkalemia (McCann et al, 2002).
    d) NALOXONE DOSE/CHILDREN
    1) LESS THAN 5 YEARS OF AGE OR LESS THAN 20 KG: 0.1 mg/kg IV/intraosseous/IM/subcutaneously maximum dose 2 mg; may repeat dose every 2 to 5 minutes until symptoms improve (Kleinman et al, 2010; Hegenbarth & American Academy of Pediatrics Committee on Drugs, 2008)
    2) 5 YEARS OF AGE OR OLDER OR GREATER THAN 20 KG: 2 mg IV/intraosseous/IM/subcutaneouslymay repeat dose every 2 to 5 minutes until symptoms improve (Kleinman et al, 2010; Hegenbarth & American Academy of Pediatrics Committee on Drugs, 2008; Krauss & Green, 2006). Although naloxone may be given via the endotracheal tube for pediatric resuscitation, optimal doses are unknown. Some experts have recommended using 2 to 3 times the IV dose (Kleinman et al, 2010)
    3) AVOIDANCE OF OPIOID WITHDRAWAL: In cases of known or suspected chronic opioid therapy, a lower dose of 0.01 mg/kg may be considered and titrated to effect to avoid withdrawal: INITIAL DOSE: 0.01 mg/kg body weight given IV. If this does not result in clinical improvement, an additional dose of 0.1 mg/kg body weight may be given. It may be given by the IM or subQ route if the IV route is not available (Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008)
    e) NALOXONE DOSE/NEONATE
    1) The American Academy of Pediatrics recommends a neonatal dose of 0.1 mg/kg IV or intratracheally from birth until age 5 years or 20 kilograms of body weight (AAP, 1989; Kleinman et al, 2010).
    2) Smaller doses (10 to 30 mcg/kg IV) have been successful in the setting of exposure via maternal administration of narcotics or administration to neonates in therapeutic doses for anesthesia (Wiener et al, 1977; Welles et al, 1984; Fischer & Cook, 1974; Brice et al, 1979).
    3) POTENTIAL OF WITHDRAWAL: The risk of precipitating withdrawal in an addicted neonate should be considered. Withdrawal seizures have been provoked in infants from opioid-abusing mothers when the infants were given naloxone at birth to stimulate breathing (Gibbs et al, 1989).
    4) In cases of inadvertent administration of an opioid overdose to a neonate, larger doses may be required. In one case of oral morphine intoxication, 0.16 milligram/kilogram/hour was required for 5 days (Tenenbein, 1984).
    f) NALOXONE/ALTERNATE ROUTES
    1) If intravenous access cannot be rapidly established, naloxone can be administered via subcutaneous or intramuscular injection, intranasally, or via inhaled nebulization in patients with spontaneous respirations.
    2) INTRAMUSCULAR/SUBCUTANEOUS ROUTES: If an intravenous line cannot be secured due to hypoperfusion or lack of adequate veins then naloxone can be administered by other routes.
    3) The intramuscular or subcutaneous routes are effective if hypoperfusion is not present (Prod Info naloxone HCl IV, IM, subcutaneous injection solution, 2008). The delay required to establish an IV, offsets the slower rate of subcutaneous absorption (Wanger et al, 1998).
    4) Naloxone Evzio(TM) is a hand-held autoinjector intended for the emergency treatment of known or suspected opioid overdose. The autoinjector is equipped with an electronic voice instruction system to assist caregivers with administration. It is available as 0.4 mg/0.4 mL solution for injection in a pre-filled auto-injector (Prod Info EVZIO(TM) injection solution, 2014).
    5) INTRANASAL ROUTE: Intranasal naloxone has been shown to be effective in opioid overdose; bioavailability appears similar to the intravenous route (Kelly & Koutsogiannis, 2002). Based on several case series of patients with suspected opiate overdose, the average response time of 3.4 minutes was observed using a formulation of 1 mg/mL/nostril by a mucosal atomization device (Kerr et al, 2009; Kelly & Koutsogiannis, 2002). However, a young adult who intentionally masticated two 25 mcg fentanyl patches and developed agonal respirations (6 breaths per minute), decreased mental status and mitotic pupils did not respond to intranasal naloxone (1 mg in each nostril) administered by paramedics. After 11 minutes, paramedics placed an IV and administered 1 mg of IV naloxone; respirations normalized and mental status improved. Upon admission, 2 additional doses of naloxone 0.4 mg IV were needed. The patient was monitored overnight and discharged the following day without sequelae. Its suggested that intranasal administration can lead to unpredictable absorption (Zuckerman et al, 2014).
    a) Narcan(R) nasal spray is supplied as a single 4 mg dose of naloxone hydrochloride in a 0.1 mL intranasal spray (Prod Info NARCAN(R) nasal spray, 2015).
    b) FDA DOSING: Initial dose: 1 spray (4 mg) intranasally into 1 nostril. Subsequent doses: Use a new Narcan(R) nasal spray and administer into alternating nostrils. May repeat dose every 2 to 3 minutes. Requirement for repeat dosing is dependent on the amount, type, and route of administration of the opioid being antagonized. Higher or repeat doses may be required for partial agonists or mixed agonist/antagonists (Prod Info NARCAN(R) nasal spray, 2015).
    c) AMERICAN HEART ASSOCIATION GUIDELINE DOSING: Usual dose: 2 mg intranasally as soon as possible; may repeat after 4 minutes (Lavonas et al, 2015). Higher doses may be required with atypical opioids (VandenHoek et al, 2010).
    d) ABSORPTION: Based on limited data, the absorption rate of intranasal administration is comparable to intravenous administration. The peak plasma concentration of intranasal administration is estimated to be 3 minutes which is similar to the intravenous route (Kerr et al, 2009). In rare cases, nasal absorption may be inhibited by injury, prior use of intranasal drugs, or excessive secretions (Kerr et al, 2009).
    6) NEBULIZED ROUTE: DOSE: A suggested dose is 2 mg naloxone with 3 mL of normal saline for suspected opioid overdose in patients with some spontaneous respirations (Weber et al, 2012).
    7) ENDOTRACHEAL ROUTE: Endotracheal administration of naloxone can be effective(Tandberg & Abercrombie, 1982), optimum dose unknown but 2 to 3 times the intravenous dose had been recommended by some (Kleinman et al, 2010).
    g) NALOXONE/CONTINUOUS INFUSION METHOD
    1) A continuous infusion of naloxone may be employed in circumstances of opioid overdose with long acting opioids (Howland & Nelson, 2011; Redfern, 1983).
    2) The patient is given an initial dose of IV naloxone to achieve reversal of opioid effects and is then started on a continuous infusion to maintain this state of antagonism.
    3) DOSE: Utilize two-thirds of the initial naloxone bolus on an hourly basis (Howland & Nelson, 2011; Mofenson & Caraccio, 1987). For an adult, prepare the dose by multiplying the effective bolus dose by 6.6, and add that amount to 1000 mL and administer at an IV infusion rate of 100 mL/hour (Howland & Nelson, 2011).
    4) Dose and duration of action of naloxone therapy varies based on several factors; continuous monitoring should be used to prevent withdrawal induction (Howland & Nelson, 2011).
    5) Observe patients for evidence of CNS or respiratory depression for at least 2 hours after discontinuing the infusion (Howland & Nelson, 2011).
    h) NALOXONE/PREGNANCY
    1) In general, the smallest dose of naloxone required to reverse life threatening opioid effects should be used in pregnant women. Naloxone detoxification of opioid addicts during pregnancy may result in fetal distress, meconium staining and fetal death (Zuspan et al, 1975). When naloxone is used during pregnancy, opioid abstinence may be provoked in utero (Umans & Szeto, 1985).
    D) HYPOTENSIVE EPISODE
    1) If CNS depression is present, administer naloxone and correct hypoxia. Hypotension should initially be treated with a saline bolus, if patient can tolerate a fluid load, then adrenergic vasopressors to raise mean arterial pressure.
    2) SUMMARY
    a) Infuse 10 to 20 milliliters/kilogram of isotonic fluid and keep the patient supine. If hypotension persists, administer dopamine or norepinephrine. Consider central venous pressure monitoring to guide further fluid therapy.
    3) DOPAMINE
    a) DOSE: Begin at 5 micrograms per kilogram per minute progressing in 5 micrograms per kilogram per minute increments as needed (Prod Info dopamine hcl, 5% dextrose IV injection, 2004). If hypotension persists, dopamine may need to be discontinued and a more potent vasoconstrictor (eg, norepinephrine) should be considered (Prod Info dopamine hcl, 5% dextrose IV injection, 2004).
    b) CAUTION: If ventricular dysrhythmias occur, decrease rate of administration (Prod Info dopamine hcl, 5% dextrose IV injection, 2004). Extravasation may cause local tissue necrosis, administration through a central venous catheter is preferred (Prod Info dopamine hcl, 5% dextrose IV injection, 2004).
    4) NOREPINEPHRINE
    a) PREPARATION: 4 milligrams (1 amp) added to 1000 milliliters of diluent provides a concentration of 4 micrograms/milliliter of norepinephrine base. Norepinephrine bitartrate should be mixed in dextrose solutions (dextrose 5% in water, dextrose 5% in saline) since dextrose-containing solutions protect against excessive oxidation and subsequent potency loss. Administration in saline alone is not recommended (Prod Info norepinephrine bitartrate injection, 2005).
    b) DOSE
    1) ADULT: Dose range: 0.1 to 0.5 microgram/kilogram/minute (eg, 70 kg adult 7 to 35 mcg/min); titrate to maintain adequate blood pressure (Peberdy et al, 2010).
    2) CHILD: Dose range: 0.1 to 2 micrograms/kilogram/minute; titrate to maintain adequate blood pressure (Kleinman et al, 2010).
    3) CAUTION: Extravasation may cause local tissue ischemia, administration by central venous catheter is advised (Peberdy et al, 2010).
    E) SEIZURE
    1) Seizures are rare, but may be a result of hypoxia or coingestants. If CNS depression is present, administer naloxone and correct hypoxia. Administer intravenous, benzodiazepines, barbiturates or propofol if seizures persist.
    2) DIAZEPAM
    a) ADULT DOSE: Initially 5 to 10 mg IV, OR 0.15 mg/kg IV up to 10 mg per dose up to a rate of 5 mg/minute; may be repeated every 5 to 20 minutes as needed (Brophy et al, 2012; Prod Info diazepam IM, IV injection, 2008; Manno, 2003).
    b) PEDIATRIC DOSE: 0.1 to 0.5 mg/kg IV over 2 to 5 minutes; up to a maximum of 10 mg/dose. May repeat dose every 5 to 10 minutes as needed (Loddenkemper & Goodkin, 2011; Hegenbarth & American Academy of Pediatrics Committee on Drugs, 2008).
    c) Monitor for hypotension, respiratory depression, and the need for endotracheal intubation. Consider a second agent if seizures persist or recur after repeated doses of diazepam .
    3) NO INTRAVENOUS ACCESS
    a) DIAZEPAM may be given rectally or intramuscularly (Manno, 2003). RECTAL DOSE: CHILD: Greater than 12 years: 0.2 mg/kg; 6 to 11 years: 0.3 mg/kg; 2 to 5 years: 0.5 mg/kg (Brophy et al, 2012).
    b) MIDAZOLAM has been used intramuscularly and intranasally, particularly in children when intravenous access has not been established. ADULT DOSE: 0.2 mg/kg IM, up to a maximum dose of 10 mg (Brophy et al, 2012). PEDIATRIC DOSE: INTRAMUSCULAR: 0.2 mg/kg IM, up to a maximum dose of 7 mg (Chamberlain et al, 1997) OR 10 mg IM (weight greater than 40 kg); 5 mg IM (weight 13 to 40 kg); INTRANASAL: 0.2 to 0.5 mg/kg up to a maximum of 10 mg/dose (Loddenkemper & Goodkin, 2011; Brophy et al, 2012). BUCCAL midazolam, 10 mg, has been used in adolescents and older children (5-years-old or more) to control seizures when intravenous access was not established (Scott et al, 1999).
    4) LORAZEPAM
    a) MAXIMUM RATE: The rate of intravenous administration of lorazepam should not exceed 2 mg/min (Brophy et al, 2012; Prod Info lorazepam IM, IV injection, 2008).
    b) ADULT DOSE: 2 to 4 mg IV initially; repeat every 5 to 10 minutes as needed, if seizures persist (Manno, 2003; Brophy et al, 2012).
    c) PEDIATRIC DOSE: 0.05 to 0.1 mg/kg IV over 2 to 5 minutes, up to a maximum of 4 mg/dose; may repeat in 5 to 15 minutes as needed, if seizures continue (Brophy et al, 2012; Loddenkemper & Goodkin, 2011; Hegenbarth & American Academy of Pediatrics Committee on Drugs, 2008; Sreenath et al, 2009; Chin et al, 2008).
    5) PHENOBARBITAL
    a) ADULT LOADING DOSE: 20 mg/kg IV at an infusion rate of 50 to 100 mg/minute IV. An additional 5 to 10 mg/kg dose may be given 10 minutes after loading infusion if seizures persist or recur (Brophy et al, 2012).
    b) Patients receiving high doses will require endotracheal intubation and may require vasopressor support (Brophy et al, 2012).
    c) PEDIATRIC LOADING DOSE: 20 mg/kg may be given as single or divided application (2 mg/kg/minute in children weighing less than 40 kg up to 100 mg/min in children weighing greater than 40 kg). A plasma concentration of about 20 mg/L will be achieved by this dose (Loddenkemper & Goodkin, 2011).
    d) REPEAT PEDIATRIC DOSE: Repeat doses of 5 to 20 mg/kg may be given every 15 to 20 minutes if seizures persist, with cardiorespiratory monitoring (Loddenkemper & Goodkin, 2011).
    e) MONITOR: For hypotension, respiratory depression, and the need for endotracheal intubation (Loddenkemper & Goodkin, 2011; Manno, 2003).
    f) SERUM CONCENTRATION MONITORING: Monitor serum concentrations over the next 12 to 24 hours. Therapeutic serum concentrations of phenobarbital range from 10 to 40 mcg/mL, although the optimal plasma concentration for some individuals may vary outside this range (Hvidberg & Dam, 1976; Choonara & Rane, 1990; AMA Department of Drugs, 1992).
    6) OTHER AGENTS
    a) If seizures persist after phenobarbital, propofol or pentobarbital infusion, or neuromuscular paralysis with general anesthesia (isoflurane) and continuous EEG monitoring should be considered (Manno, 2003). Other anticonvulsants can be considered (eg, valproate sodium, levetiracetam, lacosamide, topiramate) if seizures persist or recur; however, there is very little data regarding their use in toxin induced seizures, controlled trials are not available to define the optimal dosage ranges for these agents in status epilepticus (Brophy et al, 2012):
    1) VALPROATE SODIUM: ADULT DOSE: An initial dose of 20 to 40 mg/kg IV, at a rate of 3 to 6 mg/kg/minute; may give an additional dose of 20 mg/kg 10 minutes after loading infusion. PEDIATRIC DOSE: 1.5 to 3 mg/kg/minute (Brophy et al, 2012).
    2) LEVETIRACETAM: ADULT DOSE: 1000 to 3000 mg IV, at a rate of 2 to 5 mg/kg/min IV. PEDIATRIC DOSE: 20 to 60 mg/kg IV (Brophy et al, 2012; Loddenkemper & Goodkin, 2011).
    3) LACOSAMIDE: ADULT DOSE: 200 to 400 mg IV; 200 mg IV over 15 minutes (Brophy et al, 2012). PEDIATRIC DOSE: In one study, median starting doses of 1.3 mg/kg/day and maintenance doses of 4.7 mg/kg/day were used in children 8 years and older (Loddenkemper & Goodkin, 2011).
    4) TOPIRAMATE: ADULT DOSE: 200 to 400 mg nasogastric/orally OR 300 to 1600 mg/day orally divided in 2 to 4 times daily (Brophy et al, 2012).
    F) ACUTE LUNG INJURY
    1) ONSET: Onset of acute lung injury after toxic exposure may be delayed up to 24 to 72 hours after exposure in some cases.
    2) NON-PHARMACOLOGIC TREATMENT: The treatment of acute lung injury is primarily supportive (Cataletto, 2012). Maintain adequate ventilation and oxygenation with frequent monitoring of arterial blood gases and/or pulse oximetry. If a high FIO2 is required to maintain adequate oxygenation, mechanical ventilation and positive-end-expiratory pressure (PEEP) may be required; ventilation with small tidal volumes (6 mL/kg) is preferred if ARDS develops (Haas, 2011; Stolbach & Hoffman, 2011).
    a) To minimize barotrauma and other complications, use the lowest amount of PEEP possible while maintaining adequate oxygenation. Use of smaller tidal volumes (6 mL/kg) and lower plateau pressures (30 cm water or less) has been associated with decreased mortality and more rapid weaning from mechanical ventilation in patients with ARDS (Brower et al, 2000). More treatment information may be obtained from ARDS Clinical Network website, NIH NHLBI ARDS Clinical Network Mechanical Ventilation Protocol Summary, http://www.ardsnet.org/node/77791 (NHLBI ARDS Network, 2008)
    3) FLUIDS: Crystalloid solutions must be administered judiciously. Pulmonary artery monitoring may help. In general the pulmonary artery wedge pressure should be kept relatively low while still maintaining adequate cardiac output, blood pressure and urine output (Stolbach & Hoffman, 2011).
    4) ANTIBIOTICS: Indicated only when there is evidence of infection (Artigas et al, 1998).
    5) EXPERIMENTAL THERAPY: Partial liquid ventilation has shown promise in preliminary studies (Kollef & Schuster, 1995).
    6) CALFACTANT: In a multicenter, randomized, blinded trial, endotracheal instillation of 2 doses of 80 mL/m(2) calfactant (35 mg/mL of phospholipid suspension in saline) in infants, children, and adolescents with acute lung injury resulted in acute improvement in oxygenation and lower mortality; however, no significant decrease in the course of respiratory failure measured by duration of ventilator therapy, intensive care unit, or hospital stay was noted. Adverse effects (transient hypoxia and hypotension) were more frequent in calfactant patients, but these effects were mild and did not require withdrawal from the study (Wilson et al, 2005).
    7) However, in a multicenter, randomized, controlled, and masked trial, endotracheal instillation of up to 3 doses of calfactant (30 mg) in adults only with acute lung injury/ARDS due to direct lung injury was not associated with improved oxygenation and longer term benefits compared to the placebo group. It was also associated with significant increases in hypoxia and hypotension (Willson et al, 2015).

Enhanced Elimination

    A) SUMMARY
    1) Hemodialysis and hemoperfusion are not of value because of the large volume of distribution.

Summary

    A) TOXICITY: The toxic dose is not established and depends on individual patient tolerance.
    B) THERAPEUTIC DOSE: 2 mg orally, may repeat in 6 to 8 hr as needed; may increase dose up to 3 mg every 6 to 8 hr if needed; MAX 6 to 12 mg daily. CHRONIC PAIN: Levorphanol produces morphine-like analgesia but it is 4 to 8 times as potent as morphine and has a longer half-life. DOSE: initial, total daily dose 1/15 to 1/12 of total daily dose of oral morphine; wait 72 hours between dose adjustments. CHILDREN: Safety and effectiveness in pediatric patients have not been established.

Therapeutic Dose

    7.2.1) ADULT
    A) 2 mg orally, may repeat in 6 to 8 hours as needed; may increase dose up to 3 mg every 6 to 8 hours if needed; MAX 6 to 12 mg daily (Prod Info levorphanol tartrate oral tablets, 2011).
    B) CHRONIC PAIN: Levorphanol produces morphine-like analgesia but it is 4 to 8 times as potent as morphine and has a longer half-life. DOSE: Initial, total daily dose 1/15 to 1/12 of total daily dose of oral morphine; wait 72 hours between dose adjustments (Prod Info levorphanol tartrate oral tablets, 2011)
    7.2.2) PEDIATRIC
    A) Safety and effectiveness in pediatric patients have not been established (Prod Info levorphanol tartrate oral tablets, 2011).

Maximum Tolerated Exposure

    A) The toxic dose is not established and depends on individual patient tolerance.

Pharmacologic Mechanism

    A) Levorphanol is a potent synthetic mu-agonist opioid that exerts its action at receptors in the periventricular and periaqueductal gray matter in the brain and spinal cord, thus altering transmission and perception of pain. It produces morphine-like analgesia (Prod Info Levorphanol tartrate oral tablets, 2008).

Toxicologic Mechanism

    A) The exact mechanism of analgesic effect is unknown, but therapeutic and toxic effects are likely mediated by different opioid receptors. Mu 1: Supraspinal and peripheral analgesia, sedation, and euphoria. Mu 2: Spinal analgesia, respiratory depression, physical dependence, GI dysmotility, bradycardia and pruritus. Kappa 1: Spinal analgesia and miosis. Kappa 2: Dysphoria and psychotomimetic. Kappa 3: Supraspinal analgesia. Chronic opioid users develop tolerance to the analgesic and euphoric effects, but not to the respiratory depression effects (Nelson, 2006; Jaffe & Martin, 1990).

Physical Characteristics

    A) A white crystaline powder, soluble in water and ether (Prod Info Levorphanol tartrate oral tablets, 2008).

Molecular Weight

    A) 443.5 (Prod Info Levorphanol tartrate oral tablets, 2008)

General Bibliography

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