Pharmacologic class: Angiotensin-converting enzyme (ACE) inhibitor
Therapeutic class: Antihypertensive
Pregnancy risk category C (first trimester), D (second and third trimesters)
FDA Box Warning
• When used during second or third trimester of pregnancy, drug can cause fetal injury and even death. Discontinue as soon as pregnancy is detected.
Inhibits conversion of angiotensin I to angiotensin II, a potent vasoconstrictor; inactivates bradykinin and prostaglandins. Also increases plasma renin and potassium levels and reduces aldosterone levels, resulting in systemic vasodilation.
Injection: 1.25 mg/ml
Tablets: 2.5 mg, 5 mg, 10 mg, 20 mg
Indications and dosages
Adults: For patients not taking concomitant diuretics-initially, 5 mg P.O. once daily, increased after 1 to 2 weeks as needed to a maintenance dosage of 10 to 40 mg P.O. daily given as a single dose or in two divided doses; or 1.25 mg I.V. q 6 hours. For patients taking diuretics-initially, 2.5 mg P.O. or 0.625 mg I.V.
Children: 0.08 mg/kg P.O. once daily; may be increased based on blood pressure response up to 5 mg daily. Maximum dosage is 0.58 mg/kg/dose.
➣ Heart failure
Adults: Initially, 2.5 mg P.O. once or twice daily, increased after 1 to 2 weeks as needed to maintenance dosage of 5 to 40 mg P.O. daily given as a single dose or in two divided doses
➣ Asymptomatic left ventricular dysfunction
Adults: Initially, 2.5 mg P.O. once or twice daily, increased after 1 to 2 weeks as needed to a maximum of 20 mg/day in divided doses
• Renal impairment
• Diabetic nephropathy
• Hypertensive emergency
• Hypersensitivity to drug or other ACE inhibitors
Use cautiously in:
• renal or hepatic impairment, hypovolemia, hyponatremia, aortic stenosis, hypertrophic cardiomyopathy, cerebrovascular or cardiac insufficiency
• concurrent diuretic use
• elderly patients
• breastfeeding patients
• Give oral doses with food or beverage.
• Discontinue diuretics for 2 to 3 days before starting drug, if possible.
• Know that I.V. administration is usually reserved for patients who cannot take P.O. form.
• Be aware that I.V. administration isn't recommended for pediatric patients.
• Administer I.V. dose either undiluted or diluted in 50 ml of dextrose 5% in water, normal saline solution, dextrose 5% in normal saline solution, or dextrose 5% in lactated Ringer's solution.
• Give single I.V. dose by push or piggyback over 5 minutes. If patient is at risk for hypotension, infusion may be given over 1 hour.
• Be aware that black patients have a higher risk of angioedema.
CNS: dizziness, fatigue, headache, insomnia, drowsiness, vertigo, asthenia, paresthesia, ataxia, confusion, depression, nervousness,cerebrovascular accident
CV: orthostatic hypotension, palpitations, angina pectoris, tachycardia, peripheral edema,arrhythmias, cardiac arrest
GI: nausea, vomiting, constipation, dyspepsia, abdominal pain, dry mouth, pancreatitis
GU: proteinuria, urinary tract infection, erectile dysfunction, decreased libido,oliguria
Hematologic: agranulocytosis, bone marrow depression
Metabolic: hyponatremia,hyperkalemia Respiratory: cough, upper respiratory tract infection, asthma, bronchitis, dyspnea,eosinophilic pneumonitis
Skin: rash, alopecia, photosensitivity, diaphoresis, exfoliative dermatitis, angioedema,erythema multiforme
Other: altered taste, fever, increased appetite, anaphylactoid reactions
Drug-drug. Allopurinol: increased risk of hypersensitivity reaction
Antacids: decreased enalapril absorption Cyclosporine, indomethacin, potassiumsparing diuretics, potassium supplements: hyperkalemia
Digoxin, lithium: increased blood levels of these drugs, possible toxicity
Diuretics, nitrates, other antihypertensives, phenothiazines: additive hypotension
Nonsteroidal anti-inflammatory drugs: decreased antihypertensive response
Rifampin: decreased enalapril efficacy
Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, blood urea nitrogen (BUN), creatinine, potassium: increased levels Antinuclear antibodies: positive titer Sodium: decreased level
Drug-food. Salt substitutes containing potassium: hyperkalemia
Drug-herbs. Capsaicin: increased incidence of cough
Drug-behaviors. Acute alcohol ingestion: additive hypotension
Sun exposure: photosensitivity reaction
☞ Assess for rapid blood pressure drop leading to cardiovascular collapse, especially when giving with diuretics.
☞ In patient with renal insufficiency or renal artery stenosis, monitor for worsening renal function.
• After initial dose, observe patient closely for at least 2 hours until blood pressure has stabilized. Then continue to observe for additional hour.
• Monitor vital signs, fluid intake and output, and daily weight.
• Supervise patient during ambulation until effects of drug are known.
• Monitor liver function tests, BUN, and creatinine and electrolyte levels.
• Inform patient that drug's full effect may not occur for several weeks.
• Advise patient to report persistent dry cough with nasal congestion.
☞ Tell patient to immediately report swelling of face, eye area, tongue, lips, hands, or feet; rash, hives, or severe itching; unexplained fever; unusual tiredness; yellowing of skin or eyes; abdominal pain; or easy bruising.
• Instruct patient to move slowly when sitting up or standing, to avoid dizziness or light-headedness from sudden blood pressure decrease.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.