Bosentan lowers blood pressure in your lungs, helping your heart pump blood more efficiently.

Bosentan is used to treat pulmonary arterial hypertension (PAH) in adults and children who are at least 3 years old. It improves your ability to exercise and prevents your condition from getting worse.

Bosentan is available only under a special program from a certified pharmacy. You must be registered in the program and understand the risks and benefits of taking this medication.

Bosentan may also be used for purposes not listed in this medication guide.

Do not use bosentan if you are pregnant or think you might be pregnant. You will need to take a pregnancy test before, during, and after treatment with bosentan. Use highly effective birth control to prevent pregnancy while using bosentan and for at least 30 days after your last dose.

Certain other medicines can interact with bosentan and should not be used at the same time. Tell your doctor about all your current medicines.

Bosentan can cause severe liver problems. Your liver function will need to be tested often.

Call your doctor right away if you have have signs of liver problems such as nausea, vomiting, fever, upper stomach pain, tiredness, or jaundice (yellowing of the skin or eyes).

Bosentan is available only from a certified pharmacy under a special program.

Bosentan is usually taken 2 times per day. Your doctor may change your dose after 4 weeks of treatment. Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

You may take bosentan with or without food.

Do not swallow a dispersible tablet whole. Place it into a small amount of water and allow the tablet to disperse in the liquid. The tablet will not dissolve completely. Stir gently and drink this mixture right away.

If your doctor tells you to use only half of a dispersible tablet, break the tablet at the line scored on it and disperse only one tablet half in water. Place the unused tablet half back into the blister pack for storage, and use that half within 7 days. Do not break a tablet half into smaller pieces.

Bosentan can cause severe liver problems. Your liver function will need to be tested before you start taking bosentan, and again each month during your treatment.

Your blood cells may also need to be tested during treatment and for up to 3 months after you stop taking bosentan.

You should not stop using bosentan suddenly. Stopping suddenly may make your condition worse. Follow your doctor's instructions about tapering your dose.

Store at room temperature away from moisture and heat.

Usual Adult Dose for Pulmonary Hypertension:

Initial dose: 62.5 mg orally twice a day for 4 weeks
Maintenance dose: Following initial dose, increase to 125 mg orally twice a day

Comments:
-Doses above 125 mg twice a day did not appear to confer additional benefit sufficient enough to offset increased risk of hepatotoxicity.

Use: For the treatment of pulmonary arterial hypertension (PAH) (WHO Group 1) to improve exercise ability and to decrease clinical worsening.

Usual Pediatric Dose for Pulmonary Hypertension:

3 to 12 years:
4 kg to 8 kg: 16 mg orally twice a day
Greater than 8 kg to 16 kg: 32 mg orally twice a day
Greater than 16 kg to 24 kg: 48 mg orally twice a day
Greater than 24 kg to 40 kg: 64 mg orally twice a day

Greater than 12 years:
-Less than 40 kg: 62.5 mg orally twice a day
-Greater than 40 kg: 62.5 mg orally twice a day for 4 weeks, then increase to 125 mg orally twice a day

Use: For use in pediatric patients 3 years or older with idiopathic or congenital PAH to improve pulmonary vascular resistance, which is expected to result in an improvement in exercise ability

You should not use bosentan if you are allergic to it, or if you are pregnant or might become pregnant during treatment.

Some medicines can cause unwanted or dangerous effects when used with bosentan. Your doctor may change your treatment plan if you also use:

• cyclosporine; or

• glyburide.

Tell your doctor if you have ever had:

• liver disease;

• fluid retention;

• diabetes;

• an autoimmune disorder such as rheumatoid arthritis or psoriasis; or

• a heart or kidney transplant.

Do not use bosentan if you are pregnant or think you might be pregnant. This medicine can cause serious birth defects. Tell your doctor right away if you miss a menstrual period or think you may have become pregnant during treatment.

You will need to have a negative pregnancy test before starting this treatment. You will be re-tested every month during your treatment, and 1 month after you stop taking this medicine.

Even if you are not planning a pregnancy, you are considered able to become pregnant if:

• you have entered puberty (even if you have not yet started having periods);

• you have never had a hysterectomy or had your ovaries removed; or

• you have not gone through menopause (you have never gone 12 months in a row without a menstrual period).

While taking bosentan and for at least 30 days after your last dose, you must use a highly effective form of birth control or two methods together.

• A tubal ligation alone is an effective birth control method.

• An intrauterine device (IUD) alone is also an effective birth control method.

• If you use birth control pills, implants, injections, skin patches, or vaginal rings, you must use a back-up barrier form of birth control, such as a condom or diaphragm or cervical cap. Always use a spermicide gel or insert together with a barrier form of birth control.

• If you use only a barrier method, you must use a second barrier method as a back-up. For example, use a diaphragm or cervical cap in addition to a condom, plus a spermicide gel or insert.

• If your sexual partner has had a vasectomy, you must still use a second method of birth control--either a barrier method or a hormonal form (birth control pills, injections, skin patch, or vaginal ring).

Bosentan comes with patient instructions about acceptable forms of birth control to use while taking this medicine. Follow these directions carefully. Ask your doctor or pharmacist if you have any questions.

If you are the parent or caregiver of a female child taking this medicine, talk to the child's doctor once you notice any signs of puberty (breast development or pubic hair), even if menstrual periods have not yet begun.

Bosentan can decrease sperm count and may affect fertility in men (your ability to have children).

You should not breast-feed while using this medicine.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Talk to your doctor about drinking grapefruit juice while taking this medication.

Do not have unprotected sex if you are able to become pregnant.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include: skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.

Bosentan may cause serious side effects. Call your doctor at once if you have:

• swelling in your legs or ankles, with or without weight gain;

• a light-headed feeling, like you might pass out;

• low red blood cells (anemia)--pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands and feet;

• liver problems--nausea, vomiting, fever, upper stomach pain, tiredness, dark urine, jaundice (yellowing of the skin or eyes); or

• new lung problems--anxiety, sweating, pale skin, severe shortness of breath, wheezing, gasping for breath, cough with foamy mucus, chest pain, fast or uneven heart rate.

Common side effects of bosentan may include:

• headache, joint pain;

• low blood pressure, fainting;

• flushing (warmth, redness, or tingly feeling);

• irregular heartbeats; or

• cold symptoms such as stuffy nose, sinus pain, sneezing, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your other medicines, especially:

• rifampin;

• tacrolimus;

• warfarin (Coumadin, Jantoven);

• antifungal medication--fluconazole, itraconazole, ketoconazole, voriconazole;

• HIV/AIDS medication that contains ritonavir--Norvir, Kaletra, Technivie, Viekira, and others;

• hormonal forms of birth control--birth control pills, injections, skin patches, or implants; or

• "statin" medicine to treat high cholesterol--Crestor, Lipitor, Mevacor, Pravachol, Vytorin, Zocor, and others.

This list is not complete and many other drugs may affect bosentan. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Do not let anyone else take your medication. Ask your doctor any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.