Bosentan

Development of peripheral edema due to treatment and/or disease state (pulmonary arterial hypertension) may occur. There have also been postmarketing reports of fluid retention requiring treatment (eg, diuretics, fluid management, hospitalization) for heart failure. If clinically significant fluid retention develops (with or without weight gain), further evaluation is necessary to determine cause and appropriate treatment or discontinuation of therapy. Use with caution in patients with underlying heart failure due to potential complications from fluid retention. In a scientific statement from the American Heart Association, bosentan has been determined to be an agent that may exacerbate underlying myocardial dysfunction (magnitude: major) (AHA [Page 2016]).

Dose-related decreases in hematocrit/hemoglobin may be observed, usually within the first few weeks of therapy with subsequent stabilization of levels by 4 to 12 weeks of treatment. Monitor hemoglobin prior to treatment initiation, after 1 and 3 months, and every 3 months thereafter. Significant decreases in hemoglobin require further evaluation to determine the cause and specific management.

Bosentan is associated with transaminase elevations (ALT or AST ≥3 times ULN), and in a small number of cases may occur with elevations in bilirubin. Monitor transaminases at baseline then monthly thereafter. Adjust dosage if elevations in liver enzymes occur without symptoms of hepatic injury or elevated bilirubin. In the postmarketing surveillance (with close monitoring), there have been rare cases of unexplained hepatic cirrhosis after prolonged therapy (>12 months) in patients with multiple comorbidities and drug therapies. There have also been cases of hepatic failure. Treatment should be stopped in patients who develop elevated transaminases either in combination with symptoms of hepatic injury (unusual fatigue, jaundice, nausea, vomiting, abdominal pain, and/or fever) or elevated bilirubin (≥2 times ULN); safety of reintroduction is unknown. Avoid use in patients with baseline serum transaminases >3 times ULN at baseline (monitoring for hepatotoxicity may be more difficult) or moderate to severe hepatic impairment. The combination of hepatocellular injury (transaminase elevations >3 times ULN) and bilirubin increased ≥2 times ULN are a marker for potential serious hepatotoxicity. Transaminase elevations are dose dependent, generally asymptomatic, occur both early and late in therapy, progress slowly, and are usually reversible after treatment interruption or discontinuation. Transaminase elevations may also spontaneously reverse while continuing bosentan treatment. Con

Hypersensitivity reactions, including Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), anaphylaxis, rash and angioedema have been observed.

Decreased sperm counts have been observed in men during treatment; bosentan may have an adverse effect on spermatogenesis.

If signs of pulmonary edema occur, consider possibility of pulmonary veno-occlusive disease; may require discontinuation of bosentan. Concurrent drug therapy issues:

Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information. Special populations:

Bosentan is likely to cause major birth defects if used by pregnant women based on animal data. Therefore, pregnancy must be excluded before the start of treatment with bosentan. Throughout treatment and for 1 month after stopping bosentan, women of childbearing potential must use 2 reliable methods of contraception unless the patient has an intrauterine device (IUD) or tubal sterilization 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. Obtain monthly pregnancy tests. Other warnings/precautions:

Because of the risks of hepatotoxicity and birth defects, bosentan is only available through the Tracleer REMS Program. The Tracleer REMS Program is a component of the bosentan Risk Evaluation and Mitigation Strategy (REMS). Patients, prescribers, and pharmacies must enroll with the program. Call 1-866-228-3546 or visit http://www.tracleer.com/hcp/prescribing-tracleer.asp for more information.