Pharmacologic: endothelin receptor antagonists
Pulmonary arterial hypertension.
Antagonizes endogenous endothelin, resulting in vasodilation. Therapeutic Effects: Improved exercise capacity and delayed clinical worsening.
Adverse Reactions/Side Effects
CNS: headache. GI: HEPATOTOXICITY. F and E: fluid retention. Hemat: ↓ hemoglobin. Misc: ↓ sperm count.
PHYSICAL THERAPY IMPLICATIONS
Examination and Evaluation
Be alert for signs of hepatotoxicity including anorexia, abdominal pain, severe nausea and vomiting, yellow skin or eyes, fever, sore throat, malaise, weakness, facial edema, lethargy, and unusual bleeding or bruising. Report these signs to the physician immediately.
Assess exercise tolerance, and document possible benefits of drug therapy in reducing pulmonary hypertension and improving exercise capacity.
Absorption: Absorbed following oral administration, Bioavailability unknown.
Metabolism and Excretion: Highly metabolized.
Half-life: 15 hr (effective half-life 9 hr).
TIME/ACTION PROFILE (blood levels)
|ROUTE ||ONSET ||PEAK ||DURATION |
|PO ||unknown ||2 hr ||24 hr |
Contraindicated in: OB: Pregnancy or lactation; Moderate/severe hepatic impairment.
Use Cautiously in: Mild hepatic impairment; Concurrent use of cyclosporine or strong inhibitors of CYP2C19 and CYP3A; Pedi: safety and efficacy in children has not been established.
Drug-Drug: Blood levels may be ↑ by cyclosporine, strong CYP3A inhibitors including ketoconazole and strong 2C19 inhibitors including omeprazole.
PO (Adults): 5 mg once daily, may be increased to 10 mg once daily.