Bosentan

Bosentan is a prescription medication used to treat high blood pressure in the vessels of the lungs, known medically as pulmonary arterial hypertension (PAH) in adults and pediatric patients aged 3 years and older. Bosentan belongs to a group of drugs called endothelin receptor antagonists, which help blood vessels to relax, lowering blood pressure and allowing the heart to pump blood more efficiently.

This medication comes in tablet form and is taken twice a day, with or without food.

Common side effects of bosentan include respiratory tract infection, headache, and fainting.  

Bosentan is a prescription medicine used to treat people with certain types of pulmonary arterial hypertension (PAH), which is high blood pressure in the vessels of the lungs. Bosentan lowers high blood pressure in your lungs and lets your heart pump blood more efficiently.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Bosentan may be found in some form under the following brand names:

• Tracleer

Bosentan can cause serious side effects, including:

• Fluid retention and swelling of your ankles and legs. Bosentan can cause your body to hold too much water, and you may get swelling of your ankles and legs. Tell your healthcare provider if you have swelling of your ankles and legs that happens either with or without weight gain, or if you have more trouble with your breathing than normal. Your healthcare provider will look for the cause of this.
• Lower Sperm Count. Some men who take bosentan may have lower sperm counts. This may affect your ability to father a child. Tell your healthcare provider if fertility is a concern for you.
• Low red blood cell levels (anemia). Your healthcare provider will do blood tests to check your red blood cells during treatment with bosentan.

The most common side effects of bosentan are:

• respiratory tract infection
• headache
• fainting
• flushing
• low blood pressure
• inflamed nose passages (sinusitis)
• joint pain
• irregular heart beats

Tell your doctor if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of bosentan. For more information, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Bosentan and other medicines may affect how each other works and cause side effects. Especially tell your healthcare provider if you take:

• hormone-based birth control, such as pills, shots, patches, and implants. These birth control methods may not work as well when taken with bosentan.
• simvastatin or other "-statin" medicines used to lower cholesterol
• rifampin used for tuberculosis
• tacrolimus used to prevent rejection of liver or kidney transplant
• ketoconazole, fluconazole, itraconazole, or voriconazole used for fungal infections
• warfarin sodium used to prevent blood clots
• ritonavir used to treat HIV

There may be more than one brand name medicine. Ask your healthcare provider if you are not sure if your medicine is one that is listed above.

Bosentan is only available through a particular program for this medication. Before you begin taking bosentan, you must read and agree to all of the instructions in the program.

Bosentan can cause serious side effects including:

Liver damage.

• Liver damage may not cause symptoms at first. Only a blood test can show if you have early liver damage. You must have a blood test to check your liver function before you start bosentan and each month after that. Your healthcare provider will order these tests. Regular blood tests are important because they will help your healthcare provider adjust or stop your treatment before there is permanent damage.
• Tell your healthcare provider if you have had liver problems, including liver problems while taking other medicines. Call your healthcare provider right away if you have any of these symptoms of liver problems while taking bosentan:
  • nausea
  • vomiting
  • fever
  • unusual tiredness
  • stomach area (abdominal) pain
  • yellowing of the skin or the whites of your eyes (jaundice)

Serious birth defects.

• Bosentan can cause serious birth defects if taken during pregnancy. You must not be pregnant when you start taking bosentan or during bosentan treatment. Serious birth defects from bosentan can happen early in pregnancy. Females who are able to get pregnant must have a negative pregnancy test before starting treatment and each month during bosentan treatment.
• Talk with your healthcare provider or gynecologist (a doctor who specializes in female reproduction) to find out about how to prevent pregnancy. Do not have unprotected sex. Tell your healthcare provider right away if you miss a menstrual period or think you may be pregnant.
• Females who are able to get pregnant must use birth control (contraception) during bosentan treatment. You must choose and use two reliable forms of birth control at the same time, unless you have had a tubal sterilization, or have a Copper T 380A IUD or LNg 20 IUS These methods can be used alone.

Talk with your healthcare provider about which 2 methods of reliable birth control you should use. Your healthcare provider may recommend that you use a different method of birth control to help lower your risk of problems with your pulmonary arterial hypertension.

Do not take bosentan if you:

• are pregnant, plan to become pregnant, or become pregnant during bosentan treatment. Bosentan can cause serious birth defects.
• have a blood test that shows possible liver injury.
• take one of these medicines:
  • cyclosporine A used for psoriasis and rheumatoid arthritis, and to prevent rejection of heart or kidney transplants
  • glyburide used for diabetes
• you are allergic to any of the ingredients in bosentan. If you have a rash, hives or your lips swell after taking bosentan, it may be a sign of allergy. You should stop taking your bosentan and talk to your healthcare provider.

Grapefruit and grapefruit juice may interact with bosentan and lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor.

Tell your healthcare provider about all your medical conditions, including if you:

• have liver problems.
• are breastfeeding or plan to breastfeed.

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

This medication falls into category X. Bosentan can cause serious birth defects if taken during pregnancy. See "Drug Precautions" section for more information.

Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known if bosentan passes into your milk. You and your healthcare provider should decide if you will take bosentan or breastfeed. You should not do both.

Bosentan is only:

• prescribed by healthcare providers who are enrolled in a special program
• available to people who understand and agree to enroll in the program

Your healthcare provider will give you detailed information about the program for this medication.

• Bosentan will be mailed to you by a specialty pharmacy. You will only receive a 30-day supply of bosentan at one time.
• Take bosentan exactly as prescribed.
• Your healthcare provider will tell you how much bosentan to take and when to take it.
• In most cases, you will take 1 tablet in the morning and 1 in the evening.
• You can take bosentan with or without food.
• If you take more than the prescribed dose of bosentan, call your healthcare provider right away.
• If you miss a dose of bosentan, take your tablet as soon as you remember. Do not take 2 doses at the same time. If it is almost time for your next dose, skip the missed dose. Just take the next dose at your regular time.
• Do not stop taking bosentan unless your healthcare provider tells you to. Suddenly stopping your treatment may cause your symptoms to get worse. If you need to stop taking bosentan, speak with your healthcare provider about the right way to stop.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

• other medications you are taking
• how you respond to this medication
• your weight
• your age

The recommended dose range of bosentan in patients older than 12 years of age is 125 mg - 250 mg/day. The recommended dose range of bosentan in patients 12 years of age and younger is 32 mg - 128 mg/day.

In patients with a body weight below 40 kg but who are over 12 years of age, the recommended dose is 125 mg/day.

If you take too much bosentan call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

• Store bosentan at 68°F to 77°F (20°C-25°C).
• Keep bosentan and all medicines out of the reach of children.

WARNING: RISKS OF LIVER INJURY and TERATOGENICITY

Because of the risk of liver injury and birth defects, this medication is available only through a special restricted distribution program. Only prescribers and pharmacies registered with this program may prescribe and distribute bosentan. In addition, bosentan may be dispensed only to patients who are enrolled in and meet all conditions of the program.

Liver Injury

In clinical studies, bosentan caused at least 3-fold upper limit of normal (ULN) elevation of liver aminotransferases (ALT and AST) in about 11% of patients, accompanied by elevated bilirubin in a small number of cases. Because these changes are a marker for potential serious liver injury, serum aminotransferase levels must be measured prior to initiation of treatment and then monthly. In the postmarketing period, in the setting of close monitoring, rare cases of unexplained hepatic cirrhosis were reported after prolonged (> 12 months) therapy with bosentan in patients with multiple co-morbidities and drug therapies. There have also been reports of liver failure. The contribution of bosentan in these cases could not be excluded.

In at least one case, the initial presentation (after > 20 months of treatment) included pronounced elevations in aminotransferases and bilirubin levels accompanied by non-specific symptoms, all of which resolved slowly over time after discontinuation of bosentan. This case reinforces the importance of strict adherence to the monthly monitoring schedule for the duration of treatment and the treatment algorithm, which includes stopping bosentan with a rise of aminotransferases accompanied by signs or symptoms of liver dysfunction.

Elevations in aminotransferases require close attention. Bosentan should generally be avoided in patients with elevated aminotransferases (> 3 × ULN) at baseline because monitoring liver injury may be more difficult. If liver aminotransferase elevations are accompanied by clinical symptoms of liver injury (such as nausea, vomiting, fever, abdominal pain, jaundice, or unusual lethargy or fatigue) or increases in bilirubin ≥ 2 × ULN, treatment with bosentan should be stopped. There is no experience with the re-introduction of bosentan in these circumstances.

Teratogenicity

Bosentan is likely to cause major birth defects if used by pregnant females based on animal data. Therefore, pregnancy must be excluded before the start of treatment with bosentan. Throughout treatment and for one month after stopping bosentan, females of childbearing potential must use two reliable methods of contraception unless the patient has a tubal sterilization or Copper T 380A IUD or LNg 20 IUS inserted, in which case no other contraception is needed. Hormonal contraceptives, including oral, injectable, transdermal, and implantable contraceptives should not be used as the sole means of contraception because these may not be effective in patients receiving bosentan. Monthly pregnancy tests should be obtained.