When This Medicine Should Not Be Used:
This medicine is not right for everyone. Do not use it if you had an allergic reaction to bosentan, you are pregnant, or you are using cyclosporine or glyburide.

How to Use This Medicine:
Tablet

• Your doctor will tell you how much medicine to use. Do not use more than directed. If you take more medicine than you are supposed to, call your doctor right away.
• This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Tell your doctor about all other medicines you are using. This is especially important if you are a woman taking birth control pills while you are using bosentan.
• Some medicines can affect how bosentan works. Tell your doctor if you are also using any of the following:
  
  • Amiodarone, amprenavir, diltiazem, erythromycin, lopinavir/ritonavir, rifampin, ritonavir, sildenafil, or tacrolimus
  • An antifungal medicine (such as fluconazole, itraconazole, or ketoconazole), a blood thinner (such as warfarin), or medicine to lower cholesterol or triglycerides (such as atorvastatin or lovastatin)

Warnings While Using This Medicine:

• This medicine can cause very serious birth defects. Use 2 forms of effective birth control while you are taking this medicine, and for at least 1 month after you stop. For example, use 1 hormonal method (such as birth control pills) and 1 barrier method (such as condoms). If you miss a period or think you have become pregnant while you are taking this medicine, tell your doctor right away.
• You must have a negative pregnancy test before you will be allowed to take this medicine. You will also be required to have a pregnancy test every month during your treatment.
• Do not breastfeed while you are using this medicine.
• Tell your doctor if you have liver disease, heart disease, or lung problems.
• This medicine may cause the following problems:
  
  • Fluid retention
  • Pulmonary edema
  • Decreased sperm production
• Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
• Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments. Blood tests may be needed to check your liver function before you start this medicine and each month after that.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:
Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Chest pain or shortness of breath
• Dark urine or pale stools, nausea, vomiting, loss of appetite, or stomach pain, yellow skin or eyes
• Fast, uneven, or pounding heartbeat
• Lightheadedness, dizziness, or fainting
• Rapid weight gain, swelling in your hands, ankles, lower legs, or feet
• Unusual bleeding, bruising, or weakness
• Warmth or redness in your face, neck, arms, or upper chest

If you notice these less serious side effects, talk with your doctor:

• Muscle or joint pain
• Unusual tiredness
• Upset stomach

If you notice other side effects that you think are caused by this medicine, tell your doctor.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088