The medication ambrisentan was developed in the early 2000s as a treatment for pulmonary arterial hypertension (PAH). This drug is not a cure for PAH, but it can raise exercise tolerance and slow or delay worsening of the condition. Though this may change, as of April 2011, most people can only get the medication if they belong to a special program called the Letairis® Education and Access Program (LEAP), which monitors the drug’s effects and makes certain that patients don’t develop dangerous risk factors, like pregnancy. There are other cautions and contraindications associated with ambrisentan, in addition to a number of mild to severe side effects that may accompany use.
Researchers have discovered diverse functions of ambrisentan that make it an effective intervention for PAH. It blocks endothelin receptors, which produce chemicals that elevate blood pressure levels and cause narrowing arteries. Pulmonary pressure in the lungs is also reduced by this drug, which helps keep PAH from advancing and may improve how patients feel on a day-to-day basis. These interventions are accomplished by taking a single dose of the drug daily.
Not all patients presently have access to ambrisentan. A condition of use is to be part of LEAP, which means patients must assent to certain things. One of these is consent for pregnancy testing on a regular basis and an agreement to use effective birth control. These agreements are sought because ambrisentan causes severe birth defects in the fetus.
Additional concerns about the drug include that it may damage the liver. Patients with liver disease may be poor candidates for ambrisentan treatment. The medication also lowers male fertility, and it is not clear whether it can alter sperm to increase the risk of birth defects.
Certain medications may interact with ambrisentan, including antibiotics like cephalosporins or erythromycin derivatives. Many antiviral drugs that are used in the treatment of HIV may combine with this medication to cause negative effects. Also, antifungals or antacids can change the way the body processes the drug. To avoid interactions, patients enrolled in LEAP need to tell their doctors about all the medicines they use.
Side effects of ambrisentan may be benign or serious. Mild reactions include redness of the skin or a feeling of warmth or prickliness. Some patients report increased nasal congestion when they take this drug. Others develop headaches or stomachaches with its use.
Severe adverse reactions need emergency treatment and include allergy, jaundice, fast heartbeat, and shortness of breath. Dark urine, swollen ankles or feet, and symptoms resembling stomach flu should be reported to doctors immediately. On the other hand, many people take this drug without experiencing any minor or serious side effects.
