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SOFOSBUVIR

Classification   |    Detailed evidence-based information

Therapeutic Toxic Class

    A) Sofosbuvir is a hepatitis C virus (HCV) nucleotide analog NS5B polymerase inhibitor used to treat chronic hepatitis C viral infection.

Specific Substances

    1) PSI-7977
    2) GS-7977
    3) CAS 1190307-88-0
    1.2.1) MOLECULAR FORMULA
    1) C22-H29-F-N3-O9-P (Prod Info SOVALDI(TM) oral tablets, 2013)

Available Forms Sources

    A) FORMS
    1) Sofosbuvir is available as 400 mg tablets (Prod Info SOVALDI(TM) oral tablets, 2013).
    B) USES
    1) Sofosbuvir is indicated for the treatment of chronic hepatitis C viral (HCV) infection in adults as a component of a combination antiviral treatment regimen (Prod Info SOVALDI(TM) oral tablets, 2013).

Life Support

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

Clinical Effects

    0.2.1) SUMMARY OF EXPOSURE
    A) USES: Sofosbuvir is indicated for the treatment of chronic hepatitis C viral (HCV) infection in adults as a component of a combination antiviral treatment regimen.
    B) PHARMACOLOGY: Sofosbuvir is an antiviral agent that acts directly against the hepatitis C virus (HCV) via inhibition of the HCV NS5B RNA-dependent RNA polymerase, an enzyme essential for viral replication.
    C) EPIDEMIOLOGY: Overdose is rare.
    D) WITH THERAPEUTIC USE
    1) MOST COMMON (20% or greater): Sofosbuvir in combination with ribavirin: Fatigue and headache. Sofosbuvir in combination with peginterferon alfa and ribavirin: Fatigue, headache, nausea, insomnia, and anemia. COMMON (15% or greater): The following common adverse effects have also been reported in patients receiving sofosbuvir in combination with either ribavirin and/or peginterferon alfa: Pruritus, rash, myalgia, diarrhea, decreased appetite, neutropenia, asthenia, irritability, fever, chills, and influenza-like illness. UNCOMMON BUT POTENTIALLY SERIOUS (less than 1%): Pancytopenia in patients receiving concomitant peginterferon alfa. Psychiatric disorders such as severe depression including suicidal ideation and suicide.
    E) WITH POISONING/EXPOSURE
    1) Overdose data are limited. Signs and symptoms of an acute overdose are anticipated to be similar to excessive pharmacologic adverse events.
    0.2.20) REPRODUCTIVE
    A) Sofosbuvir is classified as FDA Pregnancy Category B. There have been no reports of effects on fetal development in animals after sofosbuvir treatment. If coadministered with ribavirin, the contraindications to ribavirin also apply to the combination regimen (eg, sofosbuvir alone, or combination therapies (ie, sofosbuvir/ledipasvir, sofosbuvir/velpatasvir)). Refer to the ribavirin prescribing information for further information on use during pregnancy.
    0.2.21) CARCINOGENICITY
    A) At the time of this review, the manufacturer does not report any carcinogenic potential.

Laboratory Monitoring

    A) Plasma concentrations are not readily available or clinically useful in the management of overdose.
    B) Monitor vital signs after significant overdose.
    C) Monitor serum electrolytes in patients with significant diarrhea.
    D) Monitor CBC with differential following significant overdose.
    E) Monitor liver enzymes for possible elevations in bilirubin following significant overdose.
    F) Monitor creatine kinase levels following significant overdose.

Treatment Overview

    0.4.2) ORAL/PARENTERAL EXPOSURE
    A) MANAGEMENT OF MILD TO MODERATE TOXICITY
    1) Treatment is symptomatic and supportive.
    B) MANAGEMENT OF SEVERE TOXICITY
    1) Treatment is symptomatic and supportive. Correct any significant electrolyte abnormalities in patients with severe diarrhea. Neutropenia may occur. Monitor serial CBC with differential. For severe neutropenia, administer colony stimulating factor (eg; filgrastim, sargramostim). In clinical trials, creatine kinase elevations of more than 10 times ULN occurred in 1% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alpha. Monitor creatine kinase levels. If severe elevations occur and there is a concern for rhabdomyolysis, treat the patient with aggressive IV fluids and consider sodium bicarbonate.
    C) DECONTAMINATION
    1) PREHOSPITAL: Consider activated charcoal if the overdose is recent, the patient is not vomiting, and is able to maintain airway.
    2) HOSPITAL: Consider activated charcoal if the overdose is recent, the patient is not vomiting, and is able to maintain airway.
    D) AIRWAY MANAGEMENT
    1) Airway management is very unlikely to be necessary unless more toxic agents are involved.
    E) ANTIDOTE
    1) None.
    F) NEUTROPENIA
    1) Administer colony stimulating factors in patients who develop severe neutropenia or neutropenic sepsis. Filgrastim: 5 mcg/kg/day IV or subQ. Sargramostim: 250 mcg/m(2)/day IV over 4 hours. Monitor CBC with differential daily until recovery has occurred. Patients with severe neutropenia should be in protective isolation.
    G) RHABDOMYOLYSIS
    1) During clinical trials, creatine kinase elevations of more than 10 times ULN occurred in 1% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alpha. Administer sufficient 0.9% saline to maintain urine output of 2 to 3 mL/kg/hr. Monitor input and output, serum electrolytes, CK, and renal function. Diuretics may be necessary to maintain urine output. Urinary alkalinization is NOT routinely recommended.
    H) ENHANCED ELIMINATION
    1) Hemodialysis is unlikely to be of value because of the high degree of protein binding. Approximately 18% of the administered dose was removed during a 4-hour hemodialysis session.
    I) PATIENT DISPOSITION
    1) HOME CRITERIA: A patient with an inadvertent exposure, that remains asymptomatic can be managed at home.
    2) OBSERVATION CRITERIA: Patients who are symptomatic and patients with deliberate overdose should be observed with frequent monitoring of vital signs. Patients that remain asymptomatic can be discharged.
    3) ADMISSION CRITERIA: Patients with severe neutropenia should be admitted to the hospital. Patients who remain symptomatic despite treatment should be admitted.
    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.
    J) PITFALLS
    1) When managing a suspected overdose, the possibility of multidrug involvement should be considered. Symptoms of overdose are similar to reported side effects of the medication.
    K) PHARMACOKINETICS
    1) Tmax occurred at approximately 0.5 to 2 hours, regardless of the dose. Protein binding: 61% to 65%. Extensive metabolism occurs in the liver. Excretion: Renal: approximately 80% was recovered in the urine (78% as GS-331007 metabolite and 3.5% as sofosbuvir). Fecal: approximately 14%. Elimination half-life: 0.4 hours. Median terminal half-life of the GS-331007 metabolite was 27 hours.
    L) DIFFERENTIAL DIAGNOSIS
    1) Includes other agents that may cause neutropenia or anemia.

Range Of Toxicity

    A) TOXICITY: A specific toxic dose has not been established. In clinical trials, the administration of a single supratherapeutic dose of sofosbuvir 1200 mg administered to 59 healthy subjects did not result in any untoward effects, and adverse events were similar in frequency and severity to those reported in the placebo and sofosbuvir 400 mg treatment groups.
    B) THERAPEUTIC DOSE: ADULT: One 400 mg tablet orally once daily in combination with pegylated interferon and ribavirin. PEDIATRIC: The safety and efficacy of sofosbuvir have not been established in pediatric patients.

Summary Of Exposure

    A) USES: Sofosbuvir is indicated for the treatment of chronic hepatitis C viral (HCV) infection in adults as a component of a combination antiviral treatment regimen.
    B) PHARMACOLOGY: Sofosbuvir is an antiviral agent that acts directly against the hepatitis C virus (HCV) via inhibition of the HCV NS5B RNA-dependent RNA polymerase, an enzyme essential for viral replication.
    C) EPIDEMIOLOGY: Overdose is rare.
    D) WITH THERAPEUTIC USE
    1) MOST COMMON (20% or greater): Sofosbuvir in combination with ribavirin: Fatigue and headache. Sofosbuvir in combination with peginterferon alfa and ribavirin: Fatigue, headache, nausea, insomnia, and anemia. COMMON (15% or greater): The following common adverse effects have also been reported in patients receiving sofosbuvir in combination with either ribavirin and/or peginterferon alfa: Pruritus, rash, myalgia, diarrhea, decreased appetite, neutropenia, asthenia, irritability, fever, chills, and influenza-like illness. UNCOMMON BUT POTENTIALLY SERIOUS (less than 1%): Pancytopenia in patients receiving concomitant peginterferon alfa. Psychiatric disorders such as severe depression including suicidal ideation and suicide.
    E) WITH POISONING/EXPOSURE
    1) Overdose data are limited. Signs and symptoms of an acute overdose are anticipated to be similar to excessive pharmacologic adverse events.

Vital Signs

    3.3.3) TEMPERATURE
    A) WITH THERAPEUTIC USE
    1) FEVER: In pooled phase 3 trial data, pyrexia occurred in 4% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 4% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 0% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, pyrexia developed in 18% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 14% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    2) CHILLS: Chills developed in 17% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 18% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243). Chills occurred in 2% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 2% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 1% of patients treated for 12 weeks with placebo (n=71) (Prod Info SOVALDI(TM) oral tablets, 2013).

Neurologic

    3.7.2) CLINICAL EFFECTS
    A) HEADACHE
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, headache occurred in 30% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 24% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 20% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, headache developed in 36% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 44% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    B) INSOMNIA
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, insomnia occurred in 16% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 15% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 4% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, insomnia developed in 25% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 29% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    C) ASTHENIA
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, asthenia occurred in 21% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 6% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 3% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, asthenia developed in 5% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 3% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    D) FEELING IRRITABLE
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, irritability occurred in 10% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 10% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 1% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, irritability developed in 13% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 16% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    E) FATIGUE
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, fatigue occurred in 30% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 38% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 24% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, fatigue developed in 59% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 55% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).

Gastrointestinal

    3.8.2) CLINICAL EFFECTS
    A) DIARRHEA
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, diarrhea occurred in 12% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 9% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 6% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, diarrhea developed in 12% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 17% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    B) NAUSEA
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, nausea occurred in 13% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 22% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 18% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, nausea developed in 34% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 29% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    C) DECREASE IN APPETITE
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, decreased appetite occurred in 6% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 6% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 10% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, decreased appetite developed in 18% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 18% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).

Hepatic

    3.9.2) CLINICAL EFFECTS
    A) INCREASED BILIRUBIN LEVEL
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, bilirubin elevations of more than 2.5 times the ULN occurred in 3% and 3% of patients treated for 12 and 24 weeks, respectively, with sofosbuvir in combination with ribavirin 1000 mg or 1200 mg/day compared with 1% of patients treated with peginterferon alfa/ribavirin for 24 weeks. Bilirubin levels peaked 1 to 2 weeks after treatment initiation and returned to baseline within 4 weeks of discontinuation. Transaminase elevations did not accompany the bilirubin increases (Prod Info SOVALDI(TM) oral tablets, 2013).

Hematologic

    3.13.2) CLINICAL EFFECTS
    A) ANEMIA
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, anemia occurred in 6% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 10% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 0% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, anemia developed in 21% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 12% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    B) NEUTROPENIA
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, neutropenia developed in 17% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 12% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243). Neutropenia occurred in less than 1% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in less than 1% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 0% of patients treated for 12 weeks with placebo (n=71) (Prod Info SOVALDI(TM) oral tablets, 2013).

Dermatologic

    3.14.2) CLINICAL EFFECTS
    A) ITCHING OF SKIN
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, pruritus occurred in 27% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 11% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 8% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, pruritus developed in 17% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 17% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    B) ERUPTION
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, rash occurred in 9% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 8% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 8% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, rash developed in 18% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 18% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).

Musculoskeletal

    3.15.2) CLINICAL EFFECTS
    A) MUSCLE PAIN
    1) WITH THERAPEUTIC USE
    a) In pooled phase 3 trial data, myalgia occurred in 9% of patients treated for 24 weeks with sofosbuvir and ribavirin (n=250), in 6% of patients treated for 12 weeks with sofosbuvir and ribavirin (n=650), and in 0% of patients treated for 12 weeks with placebo (n=71). Among patients treated with interferon regimens, myalgia developed in 14% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alfa (n=327) and in 16% of patients treated for 24 weeks with peginterferon alfa/ribavirin fixed-dose 800 mg/day (n=243) (Prod Info SOVALDI(TM) oral tablets, 2013).
    B) INCREASED CREATINE KINASE LEVEL
    1) WITH THERAPEUTIC USE
    a) During clinical trials, creatine kinase elevations of more than 10 times ULN occurred in 1% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alpha; less than 1% of patients treated for 24 weeks with peginterferon alpha/ribavirin; and in 2% of patients who received sofosbuvir/ribavirin for 12 weeks (Prod Info SOVALDI(TM) oral tablets, 2013).

Reproductive

    3.20.1) SUMMARY
    A) Sofosbuvir is classified as FDA Pregnancy Category B. There have been no reports of effects on fetal development in animals after sofosbuvir treatment. If coadministered with ribavirin, the contraindications to ribavirin also apply to the combination regimen (eg, sofosbuvir alone, or combination therapies (ie, sofosbuvir/ledipasvir, sofosbuvir/velpatasvir)). Refer to the ribavirin prescribing information for further information on use during pregnancy.
    3.20.3) EFFECTS IN PREGNANCY
    A) LACK OF INFORMATION
    1) SOFOSBUVIR/VELPATASVIR
    a) It is unknown whether sofosbuvir/velpatasvir negatively affects pregnancy or the developing fetus (Prod Info EPCLUSA(R) oral tablets , 2016).
    B) PREGNANCY CATEGORY
    1) Sofosbuvir is classified as FDA Pregnancy Category B (Prod Info SOVALDI(R) oral tablets, 2015).
    2) Combination therapy with sofosbuvir and ribavirin is contraindicated during pregnancy and in men whose female partner is pregnant. If combination therapy is required, refer to the ribavirin prescribing information for more information on use during pregnancy (Prod Info HARVONI(R) oral tablets, 2016a).
    C) RISK SUMMARY
    1) SOFOSBUVIR/LEDIPASVIR
    a) Avoid administering to pregnant women (Prod Info HARVONI(R) oral tablets, 2016).
    2) SOFOSBUVIR/VELPATASVIR
    a) COADMINISTRATION WITH RIBAVIRIN: If administered with ribavirin, the combination therapy is contraindicated in pregnant women and in men whose female partners are also pregnant. If combination therapy with ribavirin is required, refer to the ribavirin prescribing information for further data on use during pregnancy (Prod Info EPCLUSA(R) oral tablets , 2016).
    b) No adequate human data are available for sofosbuvir/velpatasvir when given as a combination drug. Administer the combination drug to a pregnant woman only if the potential benefit outweighs the potential risk to the fetus (Prod Info EPCLUSA(R) oral tablets , 2016).
    D) ANIMAL STUDIES
    1) SOFOSBUVIR
    a) There have been no reports of adverse effects on fetal development in animals administered sofosbuvir. AUC exposure to the metabolite GS-331007 over the course of gestation increased from 5- to 10-fold and 12- to 28-fold the human exposure at the recommended clinical dose (Prod Info SOVALDI(R) oral tablets, 2015).
    2) SOFOSBUVIR/LEDIPASVIR
    a) After the oral administration to pregnant rats, ledipasvir did not have observable effects on fetal development at the highest doses tested, approximately 4-fold the recommended human dose (RHD). Sofosbuvir also had no observable effects on fetal development at the highest doses tested. AUC exposure to the metabolite GS-331007 over the course of gestation was up to 17 times the RHD (Prod Info HARVONI(R) oral tablets, 2016).
    b) Sofosbuvir had no effect on embryofetal viability or fertility when administered to animals at doses approximately 5-fold the recommended human dose (RHD). Ledipasvir had no adverse effects on mating or fertility in animals; however, the mean number of corpora lutea and implantation sites were slightly reduced with doses approximately 3-fold the RHD (Prod Info HARVONI(R) oral tablets, 2016).
    3) SOFOSBUVIR/VELPATASVIR
    a) During animal studies, oral administration of sofosbuvir had no observable effects on embryofetal, prenatal, or postnatal development at the highest doses tested (up to 10 times the human exposure at the recommended human dose (RHD)). AUC exposure to the metabolite GS-331007 over the course of gestation was up to 10 times the RHD. Oral administration of velpatasvir at doses up to 31 times the human exposure at RHD also had no significant effects on embryofetal, prenatal, or postnatal development (Prod Info EPCLUSA(R) oral tablets , 2016).
    3.20.4) EFFECTS DURING BREAST-FEEDING
    A) LACK OF INFORMATION
    1) SOFOSBUVIR
    a) It is unknown whether sofosbuvir or its metabolites are excreted into human milk. Exercise caution when administering sofosbuvir to a lactating woman (Prod Info SOVALDI(R) oral tablets, 2015).
    2) SOFOSBUVIR/LEDIPASVIR
    a) It is unknown whether ledipasvir/sofosbuvir or its metabolites are excreted into human breast milk (Prod Info HARVONI(R) oral tablets, 2016).
    3) SOFOSBUVIR/VELPATASVIR
    a) It is unknown whether sofosbuvir, velpatasvir, or its metabolites are excreted into human breast milk or have effects on the breastfed infant (Prod Info EPCLUSA(R) oral tablets , 2016).
    B) BREAST MILK
    1) SOFOSBUVIR/VELPATASVIR
    a) Use in lactating women only after considering the mother's need for the drug, potential risk to the breastfed infant, and developmental and health benefits of breastfeeding. If coadministered with ribavirin, the contraindications to ribavirin also apply to the combination regimen. Refer to the ribavirin prescribing information for more further data on use during lactation (Prod Info EPCLUSA(R) oral tablets , 2016).
    C) ANIMAL STUDIES
    1) SOFOSBUVIR
    a) The sofosbuvir metabolite GS-331007 was observed in the milk of lactating rats; however, there was no effect on the nursing pups (Prod Info SOVALDI(R) oral tablets, 2015).
    2) SOFOSBUVIR/LEDIPASVIR
    a) Ledipasvir was detected in the plasma of nursing animals, while the primary metabolite of sofosbuvir (GS-331007) was observed in the milk of lactating animals. Maternal exposure was approximately 5 times the human recommended dose. No clear adverse effects on nursing offspring were reported (Prod Info HARVONI(R) oral tablets, 2016).
    3) SOFOSBUVIR/VELPATASVIR
    a) GS-331007, the primary metabolite of sofosbuvir, was observed in the milk of lactating animals. Velpatasvir was detected in the milk of lactating animals and in the plasma of nursing offspring. In both cases, no clear adverse effects on nursing offspring were reported (Prod Info EPCLUSA(R) oral tablets , 2016).
    3.20.5) FERTILITY
    A) ANIMAL STUDIES
    1) SOFOSBUVIR/LEDIPASVIR
    a) Sofosbuvir had no effect on embryofetal viability or fertility when administered to animals at doses approximately 5-fold the recommended human dose (RHD). Ledipasvir had no adverse effects on mating or fertility in animals; however, the mean number of corpora lutea and implantation sites were slightly reduced with doses approximately 3-fold the RHD (Prod Info HARVONI(R) oral tablets, 2015).
    2) SOFOSBUVIR/VELPATASVIR
    a) Sofosbuvir had no effect on embryofetal viability or fertility when administered to animals at doses approximately 4 times the recommended human dose (RHD). Velpatasvir also had no adverse effects on embryofetal viability or fertility in animals doses approximately 6 times the RHD (Prod Info EPCLUSA(R) oral tablets , 2016).

Carcinogenicity

    3.21.2) SUMMARY/HUMAN
    A) At the time of this review, the manufacturer does not report any carcinogenic potential.
    3.21.4) ANIMAL STUDIES
    A) LACK OF EFFECT
    1) Two-year carcinogenicity studies conducted in mice showed no increase in drug-related neoplasms at sofosbuvir doses up to 200 mg/kg/day in males and 600 mg/kg/day in females (7- and 30-fold, respectively, resulting in AUC exposure to the predominant circulating metabolite, GS-331007, at the recommended clinical human dose). Studies in rats also did not result in increased drug-related neoplasms with doses up to 750 mg/kg/day (13- and 17-fold in males and females, respectively, the exposure at the recommended clinical human dose) (Prod Info SOVALDI(R) oral tablets, 2014).

Genotoxicity

    A) In in vitro or in vivo assays, sofosbuvir was not genotoxic in bacterial mutagenicity, chromosome aberration using human peripheral blood lymphocytes, and in vivo mouse micronucleus assays (Prod Info SOVALDI(R) oral tablets, 2014).

Monitoring Parameters Levels

    4.1.1) SUMMARY
    A) Plasma concentrations are not readily available or clinically useful in the management of overdose.
    B) Monitor vital signs after significant overdose.
    C) Monitor serum electrolytes in patients with significant diarrhea.
    D) Monitor CBC with differential following significant overdose.
    E) Monitor liver enzymes for possible elevations in bilirubin following significant overdose.
    F) Monitor creatine kinase levels following significant overdose.

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 severe neutropenia should be admitted to the hospital. Patients who remain symptomatic despite treatment should be admitted.
    6.3.1.2) HOME CRITERIA/ORAL
    A) A patient with an inadvertent exposure, that remains asymptomatic can be managed at home.
    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) Patients who are symptomatic and patients with deliberate overdose should be observed with frequent monitoring of vital signs. Patients that remain asymptomatic can be discharged.

Monitoring

    A) Plasma concentrations are not readily available or clinically useful in the management of overdose.
    B) Monitor vital signs after significant overdose.
    C) Monitor serum electrolytes in patients with significant diarrhea.
    D) Monitor CBC with differential following significant overdose.
    E) Monitor liver enzymes for possible elevations in bilirubin following significant overdose.
    F) Monitor creatine kinase levels following significant overdose.

Oral Exposure

    6.5.1) PREVENTION OF ABSORPTION/PREHOSPITAL
    A) ACTIVATED CHARCOAL
    1) PREHOSPITAL ACTIVATED CHARCOAL ADMINISTRATION
    a) Consider prehospital administration of activated charcoal as an aqueous slurry in patients with a potentially toxic ingestion who are awake and able to protect their airway. Activated charcoal is most effective when administered within one hour of ingestion. Administration in the prehospital setting has the potential to significantly decrease the time from toxin ingestion to activated charcoal administration, although it has not been shown to affect outcome (Alaspaa et al, 2005; Thakore & Murphy, 2002; Spiller & Rogers, 2002).
    1) In patients who are at risk for the abrupt onset of seizures or mental status depression, activated charcoal should not be administered in the prehospital setting, due to the risk of aspiration in the event of spontaneous emesis.
    2) The addition of flavoring agents (cola drinks, chocolate milk, cherry syrup) to activated charcoal improves the palatability for children and may facilitate successful administration (Guenther Skokan et al, 2001; Dagnone et al, 2002).
    2) CHARCOAL DOSE
    a) 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).
    1) 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).
    b) ADVERSE EFFECTS/CONTRAINDICATIONS
    1) 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.
    2) Contraindications: unprotected airway (increases risk/severity of aspiration) , nonfunctioning gastrointestinal tract, uncontrolled vomiting, and ingestion of most hydrocarbons (Chyka et al, 2005).
    6.5.2) PREVENTION OF ABSORPTION
    A) ACTIVATED CHARCOAL
    1) CHARCOAL ADMINISTRATION
    a) 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.
    2) CHARCOAL DOSE
    a) 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).
    1) 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).
    b) ADVERSE EFFECTS/CONTRAINDICATIONS
    1) 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.
    2) 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) SUPPORT
    1) MANAGEMENT OF MILD TO MODERATE TOXICITY
    a) Treatment is symptomatic and supportive.
    2) MANAGEMENT OF SEVERE TOXICITY
    a) Treatment is symptomatic and supportive. Correct any significant electrolyte abnormalities in patients with severe diarrhea. Neutropenia may occur. Monitor serial CBC with differential. For severe neutropenia, administer colony stimulating factor (eg; filgrastim, sargramostim).
    B) MONITORING OF PATIENT
    1) Plasma concentrations are not readily available or clinically useful in the management of overdose.
    2) Monitor vital signs after significant overdose.
    3) Monitor serum electrolytes in patients with significant diarrhea.
    4) Monitor CBC with differential following significant overdose.
    5) Monitor liver enzymes for possible elevations in bilirubin following significant overdose.
    6) Monitor creatine kinase levels following significant overdose.
    C) NEUTROPENIA
    1) There is little data on the use of hematopoietic colony stimulating factors to treat neutropenia after drug overdose or idiosyncratic reactions. These agents have been shown to shorten the duration of severe neutropenia in patients receiving cancer chemotherapy (Hartman et al, 1997; Stull et al, 2005). They have also been used to treat agranulocytosis induced by nonchemotherapy drugs (Beauchesne & Shalansky, 1999). They may be considered in patients with severe neutropenia who have or are at significant risk for developing febrile neutropenia.
    a) Filgrastim: The usual starting dose in adults is 5 micrograms/kilogram/day by intravenous infusion or subcutaneous injection (Prod Info NEUPOGEN(R) injection, 2006).
    b) Sargramostim: Usual dose is 250 micrograms/square meter/day infused IV over 4 hours (Prod Info LEUKINE(R) injection, 2006).
    c) Monitor CBC with differential.
    D) RHABDOMYOLYSIS
    1) During clinical trials, creatine kinase elevations of more than 10 times ULN occurred in 1% of patients treated for 12 weeks with sofosbuvir in combination with ribavirin and peginterferon alpha; less than 1% of patients treated for 24 weeks with peginterferon alpha/ribavirin; and in 2% of patients who received sofosbuvir/ribavirin for 12 weeks (Prod Info SOVALDI(TM) oral tablets, 2013).
    2) SUMMARY: Early aggressive fluid replacement is the mainstay of therapy and may help prevent renal insufficiency. Diuretics such as mannitol or furosemide may be added if necessary to maintain urine output but only after volume status has been restored as hypovolemia will increase renal tubular damage. Urinary alkalinization is NOT routinely recommended.
    3) Initial treatment should be directed towards controlling acute metabolic disturbances such as hyperkalemia, hyperthermia, and hypovolemia. Control seizures, agitation, and muscle contractions (Erdman & Dart, 2004).
    4) FLUID REPLACEMENT: Early and aggressive fluid replacement is the mainstay of therapy to prevent renal failure. Vigorous fluid replacement with 0.9% saline (10 to 15 mL/kg/hour) is necessary even if there is no evidence of dehydration. Several liters of fluid may be needed within the first 24 hours (Walter & Catenacci, 2008; Camp, 2009; Huerta-Alardin et al, 2005; Criddle, 2003; Polderman, 2004). Hypovolemia, increased insensible losses, and third spacing of fluid commonly increase fluid requirements. Strive to maintain a urine output of at least 1 to 2 mL/kg/hour (or greater than 150 to 300 mL/hour) (Walter & Catenacci, 2008; Camp, 2009; Erdman & Dart, 2004; Criddle, 2003). To maintain a urine output this high, 500 to 1000 mL of fluid per hour may be required (Criddle, 2003). Monitor fluid input and urine output, plus insensible losses. Monitor for evidence of fluid overload and compartment syndrome; monitor serum electrolytes, CK, and renal function tests.
    5) DIURETICS: Diuretics (eg, mannitol or furosemide) may be needed to ensure adequate urine output and to prevent acute renal failure when used in combination with aggressive fluid therapy. Loop diuretics increase tubular flow and decrease deposition of myoglobin. These agents should be used only after volume status has been restored, as hypovolemia will increase renal tubular damage. If the patient is maintaining adequate urine output, loop diuretics are not necessary (Vanholder et al, 2000).
    6) URINARY ALKALINIZATION: Alkalinization of the urine is not routinely recommended, as it has never been documented to reduce nephrotoxicity, and may cause complications such as hypocalcemia and hypokalemia (Walter & Catenacci, 2008; Huerta-Alardin et al, 2005; Brown et al, 2004; Polderman, 2004). Retrospective studies have failed to demonstrate any clinical benefit from the use of urinary alkalinization (Brown et al, 2004; Polderman, 2004; Homsi et al, 1997).

Enhanced Elimination

    A) HEMODIALYSIS
    1) Hemodialysis is UNLIKELY to be of value because of the high degree of protein binding.
    2) Approximately 18% of the administered dose was removed during a 4-hour hemodialysis session (Prod Info SOVALDI(TM) oral tablets, 2013).

Summary

    A) TOXICITY: A specific toxic dose has not been established. In clinical trials, the administration of a single supratherapeutic dose of sofosbuvir 1200 mg administered to 59 healthy subjects did not result in any untoward effects, and adverse events were similar in frequency and severity to those reported in the placebo and sofosbuvir 400 mg treatment groups.
    B) THERAPEUTIC DOSE: ADULT: One 400 mg tablet orally once daily in combination with pegylated interferon and ribavirin. PEDIATRIC: The safety and efficacy of sofosbuvir have not been established in pediatric patients.

Therapeutic Dose

    7.2.1) ADULT
    A) SOFOSBUVIR
    1) The recommended dose is 400 mg tablet orally once daily in combination with ribavirin or in combination with pegylated interferon and ribavirin (Prod Info SOVALDI(TM) oral tablets, 2013).
    B) SOFOSBUVIR/LEDIPASVIR
    1) The recommended dose is 1 tablet (ledipasvir 90 mg/sofosbuvir 400 mg) orally once daily (Prod Info HARVONI(R) oral tablets, 2015).
    C) SOFOSBUVIR/VELPATASVIR
    1) The usual dosage is 1 tablet (sofosbuvir 400 mg/velpatasvir 100 mg) orally once daily for 12 weeks (Prod Info EPCLUSA(R) oral tablets , 2016).
    7.2.2) PEDIATRIC
    A) SOFOSBUVIR
    1) The safety and efficacy of sofosbuvir have not been established in pediatric patients (Prod Info SOVALDI(TM) oral tablets, 2013).
    B) SOFOSBUVIR/LEDIPASVIR
    1) The safety and efficacy of ledipasvir/sofosbuvir have not been established in pediatric patients (Prod Info HARVONI(R) oral tablets, 2015).
    C) SOFOSBUVIR/VELPATASVIR
    1) The safety and efficacy of sofosbuvir/velpatasvir have not been established in pediatric patients (Prod Info EPCLUSA(R) oral tablets , 2016).

Maximum Tolerated Exposure

    A) In clinical trials, the administration of a single supratherapeutic dose of sofosbuvir 1200 mg administered to 59 healthy subjects did not result in any untoward effects, and adverse events were similar in frequency and severity to those reported in the placebo and sofosbuvir 400 mg treatment groups (Prod Info SOVALDI(TM) oral tablets, 2013).

Pharmacologic Mechanism

    A) Sofosbuvir is an antiviral agent that acts directly against the hepatitis C virus (HCV) via inhibition of the HCV NS5B RNA-dependent RNA polymerase. Intracellular metabolism converts sofosbuvir, a nucleotide prodrug, into the pharmacologically active uridine analog triphosphate (GS-461203), which can be incorporated into HCV RNA via the NS5B polymerase where it acts as a chain terminator (Prod Info SOVALDI(TM) oral tablets, 2013).

Physical Characteristics

    A) A white to off-white crystalline solid; solubility of 2 mg/mL or greater across the pH range of 2 to 7.7 at 37 degrees C and is slightly soluble in water (Prod Info SOVALDI(TM) oral tablets, 2013).

Molecular Weight

    A) 529.45 (Prod Info SOVALDI(TM) oral tablets, 2013)

General Bibliography

    1) Alaspaa AO, Kuisma MJ, Hoppu K, et al: Out-of-hospital administration of activated charcoal by emergency medical services. Ann Emerg Med 2005; 45:207-12.
    2) Beauchesne MF & Shalansky SJ: Nonchemotherapy drug-induced agranulocytosis: a review of 118 patients treated with colony-stimulating factors. Pharmacotherapy 1999; 19(3):299-305.
    3) Brown CV, Rhee P, Chan L, et al: Preventing renal failure in patients with rhabdomyolysis: do bicarbonate and mannitol make a difference?. J Trauma 2004; 56(6):1191-1196.
    4) Camp NE: Drug- and toxin-induced Rhabdomyolysis. J Emerg Nurs 2009; 35(5):481-482.
    5) Chyka PA, Seger D, Krenzelok EP, et al: Position paper: Single-dose activated charcoal. Clin Toxicol (Phila) 2005; 43(2):61-87.
    6) Criddle LM: Rhabdomyolysis. Pathophysiology, recognition, and management. Crit Care Nurse 2003; 23(6):14-22, 24-26, 28.
    7) Dagnone D, Matsui D, & Rieder MJ: Assessment of the palatability of vehicles for activated charcoal in pediatric volunteers. Pediatr Emerg Care 2002; 18:19-21.
    8) Elliot CG, Colby TV, & Kelly TM: Charcoal lung. Bronchiolitis obliterans after aspiration of activated charcoal. Chest 1989; 96:672-674.
    9) Erdman AR & Dart RC: Rhabdomyolysis. In: Dart RC, Caravati EM, McGuigan MA, et al, eds. Medical Toxicology, 3rd ed. Lippincott Williams & Wilkins, Philadelphia, PA, 2004, pp 123-127.
    10) FDA: Poison treatment drug product for over-the-counter human use; tentative final monograph. FDA: Fed Register 1985; 50:2244-2262.
    11) Golej J, Boigner H, Burda G, et al: Severe respiratory failure following charcoal application in a toddler. Resuscitation 2001; 49:315-318.
    12) Graff GR, Stark J, & Berkenbosch JW: Chronic lung disease after activated charcoal aspiration. Pediatrics 2002; 109:959-961.
    13) Guenther Skokan E, Junkins EP, & Corneli HM: Taste test: children rate flavoring agents used with activated charcoal. Arch Pediatr Adolesc Med 2001; 155:683-686.
    14) Harris CR & Filandrinos D: Accidental administration of activated charcoal into the lung: aspiration by proxy. Ann Emerg Med 1993; 22:1470-1473.
    15) Hartman LC, Tschetter LK, Habermann TM, et al: Granulocyte colony-stimulating factor in severe chemotherapy-induced afebrile neutropenia.. N Engl J Med 1997; 336:1776-1780.
    16) Homsi E, Barreiro MF, Orlando JM, et al: Prophylaxis of acute renal failure in patients with rhabdomyolysis. Ren Fail 1997; 19(2):283-288.
    17) Huerta-Alardin AL, Varon J, & Marik PE: Bench-to-bedside review: Rhabdomyolysis -- an overview for clinicians. Crit Care 2005; 9(2):158-169.
    18) None Listed: Position paper: cathartics. J Toxicol Clin Toxicol 2004; 42(3):243-253.
    19) Polderman KH: Acute renal failure and rhabdomyolysis. Int J Artif Organs 2004; 27(12):1030-1033.
    20) Pollack MM, Dunbar BS, & Holbrook PR: Aspiration of activated charcoal and gastric contents. Ann Emerg Med 1981; 10:528-529.
    21) Product Information: EPCLUSA(R) oral tablets , sofosbuvir velpatasvir oral tablets. Gilead Sciences Inc (per FDA), Foster City, CA, 2016.
    22) Product Information: HARVONI(R) oral tablets, ledipasvir sofosbuvir oral tablets. Gilead Sciences, Inc. (per manufacturer), Foster City, CA, 2016a.
    23) Product Information: HARVONI(R) oral tablets, ledipasvir sofosbuvir oral tablets. Gilead Sciences, Inc.(per manufacturer), Foster City, CA, 2015.
    24) Product Information: HARVONI(R) oral tablets, ledipasvir, sofosbuvir oral tablets. Gilead Sciences Inc. (per manufacturer), Foster City, CA, 2016.
    25) Product Information: LEUKINE(R) injection, sargramostim injection. Berlex, Seattle, WA, 2006.
    26) Product Information: NEUPOGEN(R) injection, filgrastim injection. Amgen,Inc, Thousand Oaks, CA, 2006.
    27) Product Information: SOVALDI(R) oral tablets, sofosbuvir oral tablets. Gilead Sciences, Inc. (per FDA), Foster City, CA, 2015.
    28) Product Information: SOVALDI(R) oral tablets, sofosbuvir oral tablets. Gilead Sciences, Inc. (per manufacturer), Foster City, CA, 2014.
    29) Product Information: SOVALDI(TM) oral tablets, sofosbuvir oral tablets. Gilead Sciences, Inc. (per manufacturer), Foster City, CA, 2013.
    30) Rau NR, Nagaraj MV, Prakash PS, et al: Fatal pulmonary aspiration of oral activated charcoal. Br Med J 1988; 297:918-919.
    31) Spiller HA & Rogers GC: Evaluation of administration of activated charcoal in the home. Pediatrics 2002; 108:E100.
    32) Stull DM, Bilmes R, Kim H, et al: Comparison of sargramostim and filgrastim in the treatment of chemotherapy-induced neutropenia. Am J Health Syst Pharm 2005; 62(1):83-87.
    33) Thakore S & Murphy N: The potential role of prehospital administration of activated charcoal. Emerg Med J 2002; 19:63-65.
    34) Vanholder R, Sever MS, Erek E, et al: Rhabdomyolysis. J Am Soc Nephrol 2000; 11(8):1553-1561.
    35) Walter LA & Catenacci MH: Rhabdomyolysis. Hosp Physician 2008; 44(1):25-31.