BOE-sen-tan 
Therapeutic Classification: vasodilators
Pharmacologic Classification: endothelin receptor antagonists
Absorption: 50% absorbed following oral administration in normal patients.
Distribution: 18 L.
Protein Binding: >98%.
Metabolism/Excretion: Highly metabolized; one metabolite contributes to pharmacologic activity. Eliminated via biliary excretion; <3% excreted in urine.
Half-life: 5 hr.
Contraindicated in:
Use Cautiously in:
CV: edema, hypotension, palpitations.
Derm: DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS), flushing, pruritus, rash.
EENT: nasopharyngitis.
GI: HEPATOTOXICITY, dyspepsia.
GU: ↓sperm counts.
Hemat: anemia.
Neuro: headache, fatigue.
Misc: ANAPHYLAXIS, ANGIOEDEMA.
Drug-Drug:
10 days) (if initiating ritonavir in patient already receiving bosentan, discontinue bosentan for 36 hr before initiating ritonavir; can resume bosentan after 10 days at 62.5 mg once daily or every other day).
5 times the upper limit of normal, confirm level with a second test. If confirmed, reduce dose or interrupt therapy and monitor AST and ALT every 2 wk. If AST and ALT return to pretreatment levels, continue therapy or resume therapy at starting dose and recheck AST and ALT within 3 days.If AST and ALT are >5 and 8 times the upper limit of normal, confirm level with a second test. If confirmed, stop therapy and monitor AST and ALT every 2 wk. Once AST and ALT return to normal levels, reintroduce therapy at starting dose and recheck AST and ALT levels within 3 days. If AST and ALT levels are >8 times the upper limit of normal if clinical symptoms of liver injury (nausea, vomiting, fever, abdominal pain, jaundice, unusual lethargy or fatigue) occur, or if bilirubin levels are 2 times the upper limit of normal, discontinue therapy permanently.NDC Code*