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Pregnancy Category: X
Pharmacologic: endothelin receptor antagonists
Pharmacologic: endothelin receptor antagonists
Pulmonary arterial hypertension (WHO Group 1).
Antagonizes endogenous endothelin, resulting in vasodilation.
Improved exercise capacity and delayed clinical worsening.
Absorption: Absorbed following oral administration. Bioavailability unknown.
Protein Binding: 99%.
Metabolism and Excretion: Highly metabolized.
Half-life: 15 hr (effective half-life 9 hr).
Time/action profile (blood levels)
|PO||unknown||2 hr||24 hr|
Contraindicated in: Obstetric / Lactation: Pregnancy or lactation; Idiopathic pulmonary fibrosisModerate/severe hepatic impairment; Significant anemia.
Use Cautiously in: Mild hepatic impairment; Pediatric: Safety and efficacy not established.
Adverse Reactions/Side Effects
Central nervous system
- headache (most frequent)
- peripheral edema (most frequent)
- ↓ sperm count
- pulmonary veno-occlusive disease (life-threatening)
- ↓ hemoglobin (most frequent)
Drug-Drug interactionBlood levels may be ↑ by cyclosporine ; do not exceed ambrisentan dose of 5 mg once daily.
Oral (Adults) 5 mg once daily, may ↑ to 10 mg once daily.
Tablets: 5 mg, 10 mg
- Assess for signs and symptoms of primary pulmonary hypertension (dyspnea, exercise intolerance) prior to and periodically during therapy.
- Assess for peripheral edema during therapy. If clinically significant peripheral edema occurs, with or without weight gain, evaluate for underlying cause, such as heart failure, and treat.
- Monitor for symptoms of acute pulmonary edema (dyspnea, cough with frothy sputum, anxiety, restlessness, palpitations) during initiation of therapy. Consider the possibility of pulmonary veno-occlusive disease; if confirmed discontinue ambrisentan.
- Lab Test Considerations: Obtain pregnancy test prior to, monthly during therapy, and 1 month following completion of therapy.
- Monitor hemoglobin prior to and at 1 mo and periodically during therapy. May cause ↓ hemoglobin; usually occurs during first few weeks and stabilizes. If clinically significant and other causes have been excluded, discontinue therapy.
Potential Nursing DiagnosesImpaired gas exchange (Indications)
Deficient knowledge, related to medication regimen (Patient/Family Teaching)
- Only available through a special restricted distribution program called Letairis REMS due to risks of birth defects. Frmale patients must be enrolled in Letarin REMS and re-enrolled after first year and then yearly. A limited number of pharmacies are certified to dispense ambrisentan. Provide patients with telephone number (1-866-664-5327) and website (www.letairisrems.com) for information on how to obtain medication.
- Oral: May be administered without regard to food. Tablets should be swallowed whole; do not crush, break or chew.
- Instruct patient to take ambrisentan as directed, at the same time each day. Review medication guide and patient education brochures with every patient. Explain Letarin REMS to patient. Take missed dose as soon as remembered that day. Take next dose at regular time; do not take two doses at the same time to make up for missed dose.
- Advise patient to notify health care professional promptly if symptoms of fluid retention (swelling of hands, legs, ankles, feet or all over the body) or hepatotoxicity (anorexia, nausea, vomiting, fever, malaise, fatigue, right upper quadrant abdominal discomfort, jaundice, dark urine or itching) occur.
- May cause fetal harm if taken during pregnancy. Inform patients a pregnancy test is required prior to beginning therapy and acceptable methods of contraception (one highly effective form of contraception: intrauterine devices [IUD], contraceptive implants, or tubal sterilization or a combination of methods: [hormone method with a barrier method or two barrier methods]) must be used throughout therapy and for 1 mo following discontinuationIf a partner’s vasectomy is method of contraception chosen, a hormone or barrier method must be used along with this method. Educate women of childbearing years on the use of emergency contraception in the case of unprotected sex or contraceptive failure.
- Inform patients that ambrisentan may cause low sperm count.
- Advise patient of the importance of regular liver and hemoglobin testing.
- Improved exercise capacity and decreased rate of clinical progression in patients with primary pulmonary hypertension.
indications This drug is used to treat pulmonary arterial hypertension, alone or in combination with other antihypertensives.
contraindications Pregnancy, breastfeeding and known hypersensitivity to this drug prohibits its use.
adverse effects Adverse effects of this drug include headache, fever, flushing, orthostatic hypotension, hypotension, peripheral edema, sinusitis, rhinitis, abdominal pain, constipation, anemia, rash, pharyngitis, and dyspnea.