Why is this medication prescribed?Bosentan is used to treat pulmonary arterial hypertension (PAH, high blood pressure in the vessels that carry blood to the lungs). Bosentan may improve the ability to exercise and slow the worsening of symptoms in patients with PAH. Bosentan is in a class of medications called endothelin receptor antagonists. It works by stopping the action of endothelin, a natural substance that causes blood vessels to narrow and prevents normal blood flow in people who have PAH.
How should this medication be used?Bosentan comes as a tablet to take by mouth. It is usually taken with or without food twice a day in the morning and evening. To help you remember to take bosentan, take it at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take bosentan exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Your doctor will probably start you on a low dose of bosentan and increase your dose after 4 weeks.
Bosentan controls the symptoms of PAH but does not cure it. It may take 1-2 months or longer before you feel the full benefit of bosentan. Continue to take bosentan even if you feel well. Do not stop taking bosentan without talking to your doctor. If you suddenly stop taking bosentan, your symptoms may get worse. Your doctor may decrease your dose gradually.
Are there other uses for this medicine?This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking bosentan,
- tell your doctor and pharmacist if you are allergic to bosentan, any other medications, or corn.
- do not take cyclosporine (Sandimmune, Neoral) or glyburide (DiaBeta, Glynase, Micronase, others) while taking bosentan.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention any of the following: anticoagulants ('blood thinners') such as warfarin; cholesterol-lowering medications (statins) such as atorvastatin (Lipitor), fluvastatin (Lescol), lovastatin (Mevacor), pravastatin (Pravachol), and simvastatin (Zocor); hormonal contraceptives (birth control pills patches, rings, shots, implants, and intrauterine devices); ketoconazole (Nizoral); and medications for diabetes. Many other medications may also interact with bosentan, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you have or have ever had anemia (condition in which red blood cells do not bring enough oxygen to the organs) or heart disease.
What special dietary instructions should I follow?Talk to your doctor about drinking grapefruit juice while taking this medication.
What side effects can this medication cause?Bosentan may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- runny nose, sore throat, and other cold symptoms
- swelling of the arms, hands, feet, ankles, or lower legs
- sudden weight gain
- fast, pounding, or irregular heartbeat
- blurred vision
- pale skin
- shortness of breath
Bosentan may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/Safety/MedWatch] or by phone [1-800-332-1088].
What should I do if I forget to take a dose?Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What should I do in case of overdose?In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include:
- upset stomach
- fast heartbeat
- blurred vision
What storage conditions are needed for this medication?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). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
What other information should I know?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.
Important warningFor female patients:
Do not take bosentan if you are pregnant or plan to become pregnant. Bosentan may harm the fetus. If you are sexually active and able to become pregnant, you should not begin taking bosentan until a pregnancy test has shown that you are not pregnant. You must use a reliable method of birth control and be tested for pregnancy every month during your treatment. Hormonal contraceptives (birth control pills, patches, rings, shots, implants, and intrauterine devices) may not work well when used with bosentan and should not be used as your only method of birth control. Talk to your doctor about birth control methods that will work for you. Call your doctor immediately if you miss a period or think that you may be pregnant while you are taking bosentan.
For male and female patients:
Bosentan may cause liver damage. Tell your doctor if you have or have ever had liver disease. If you experience any of the following symptoms, call your doctor immediately: upset stomach, vomiting, fever, stomach pain, yellowing of the skin or eyes, or extreme tiredness.
Keep all appointments with your doctor and the laboratory. Your doctor will order a blood test to be sure your liver is working normally before you start taking bosentan and every month during your treatment. Bosentan may damage the liver without causing symptoms. Regular blood tests are the only way to find liver damage before it becomes permanent and severe.
Bosentan is not available at retail pharmacies. Your medication will be mailed to you from a central pharmacy. This program is required to be sure that all patients who receive the medication are tested for liver damage and pregnancy. Ask your doctor if you have any questions about how you will receive your medication.
You will receive the manufacturer's patient information sheet (Medication Guide) when you begin treatment with bosentan and each time you refill the prescription. Read the information carefully each time and ask your doctor or pharmacist if you have any questions. You also can obtain the Medication Guide from the FDA website: http://www.fda.gov/Drugs.
Talk to your doctor about the risks of taking bosentan.