Bosentan
Bosentan
Type of Drug Endothelia receptor antagonist.
Prescribed For
Pulmonary arterial hypertension.
General Information
These drugs lower blood pressure by working on the endothelin system. Endothelia is a hormone that plays an important role in maintaining blood pressure. It is normally found in blood vessels, but endothelin levels are very high in the blood and lungs of people with pulmonary arterial hypertension. People with this condition have high blood pressure, trouble breathing, and get very tired even when walking or doing other moderate exercising. Pulmonary arterial hypertension can be fatal.
Cautions and Warnings
These drugs should not be used by those who are allergic or sensitive to any of their ingredients.
Bosentan can cause liver injury. People taking these drugs should have their liver enzymes checked monthly. Enzyme increases can be a sign of liver injury and may be a reason to stop taking bosentan.
These drugs are broken down in the liver. People with liver damage should take them with caution.
These drugs should not be taken during pregnancy as they are likely to cause birth defects (see “Special Populations”).
These drugs cause a reduction in red blood cells, leading to anemia. Larger doses of bosentan cause a greater loss of red blood cells.
Possible Side Effects
Ambrisentan
Most side effects are mild. Only stuffy nose increases with increased dosage.
V Most common: swelling k%) -aims or legs, stuffy nose, si1)u6fis, flushing, heart palpitations, abdominal pain, constipation, difficulty breathing, and headache.
Bosentan
♦ Most common: headache and sore throat and nose.
Drug Interactions
• It is possible that bosentan may cause failure of hormonal contraceptives.
• Cyclosporine, used to prevent transplant rejection, increases blood levels of bosentan and ambrisentan. Do not combine these drugs.
• Mixing glyburide, an antidiabetes drug, with bosentan increases the risk of elevated liver enzyme levels. Do not combine these drugs.
• Ketoconazole greatly increases blood levels of bosentan by slowing its breakdown in the liver.
• Combining bosentan with a statin-type cholesterol - lowering drug such as simvastatin, lovastatin, or atorvastatin reduces the amount of statin drug in the blood. Dose increases may be needed.
• Bosentan can reduce the amount of warfarin in the blood by
about 1/3. Changes in warfarin dosage may be needed.
• Combining ambrisentan with atanazavir, clarithromycin, indinavir, itraconazole, ketoconazole, nelfinavir, ritonavir, omeprazole, saquinavir,or telithromycin may increase the amount of ambrisentan in the blood. Caution is advised.
• Combining ambrisentan with rifampin may reduce the
amount of ambrisentan in the blood. Caution is advised.
Food Interactions
These drugs may be taken with or without food.
U’Suk Dose
Ambrisentan
Adult (age 18 and over): 5-10 mg once a day. Do not crush, split, or chew these tablets.
Child: not recommended.
Possible Side Effects (continued)
♦ Common: flushing, abnormal liver blood pressure, and heart
♦ Less common: upset stomach, tiredness.
ver function, leg swelling, palpitations.
, swelling, itching, anemia,
Bosentan
Adult (age 18 and over): 62.5 mg twice a day for 4 weeks, then
125 mg twice a day.
Child: not recommended.
Overdosage
Massive overdose may result in severe lowering of blood pressure, requiring emergency attention. The most common effects associated with overdosage are headache, low blood pressure, increased heart rate, and nausea and vomiting. Overdose victims should be taken to a hospital emergency room for treatment. ALWAYS bring the prescription bottle or container.
Special Information
Do not stop taking these drugs without gradually reducing the dosage as instructed by your doctor.
If you forget to take a dose, take it as soon as you remember. If it is almost time for your next dose, skip the dose you forgot and continue with your regular schedule. Do not take a double dose.
Contact your doctor at once if you develop severe itching, yellowing of the skin or eyes, tiredness, swelling in the arms or legs, nausea, vomiting, fever, or abdominal pain.
Doctors must enroll in special restricted distribution programs before they can prescribe these medicines, because of the risks of liver injury and birth defects associated with them. These medicines are not available in regular pharmacies but are mailed to you from a central pharmacy only after the testing and other program requirements have been met by your doctor.
Special Populations
Pregnancy/Breast-feeding: These medicines are very likely to cause major birth defects and should not be taken by pregnant women. Women must be sure they are not pregnant before beginning these treatments.
Women should also use non-hormone contraceptives while on these drugs. Hormone-based contraceptives such as birth control pills, injections, and implants may not work in women taking Wst m or ambrisentan.
It is not known if either of these medicines passes into breast milk. Nursing mothers should use infant formula.
Seniors: The greater chance of kidney, liver, and cardiac function side effects in seniors may affect drug dosage. Seniors may also experience more swelling in the arms or legs.