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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 may cause fetal injury and death. Discontinue as soon as possible when pregnancy is detected.
Prevents conversion of angiotensin I to angiotensin II, which leads to decreased vasoconstriction and, ultimately, to lower blood pressure. Also decreases blood pressure by increasing plasma renin secretion from kidney and reducing aldosterone secretion from adrenal cortex. Decreased aldosterone secretion prevents sodium and water retention.
Tablets: 12.5 mg, 25 mg, 50 mg, 100 mg
Indications and dosages
Adults: 12.5 to 25 mg P.O. two to three times daily; may be increased up to 150/mg/day at 1- to 2-week intervals. Usual dosage is 50 mg t.i.d. If patient is receiving diuretics, start with 6.25 to 12.5 mg P.O. two to three times daily. If blood pressure isn't adequately controlled after 1 to 2 weeks, add diuretic, as prescribed. If further blood pressure decrease is needed, dosage may be raised to 150 mg P.O. t.i.d. while patient continues on diuretic. Maximum dosage is 450 mg/day.
➣ Heart failure
Adults: Usual initial dosage is 25 mg P.O. t.i.d. After increasing to 50 mg P.O. t.i.d. (if indicated), do not increase dosage further for 2 weeks, to determine satisfactory response. Don't exceed 450 mg/day.
➣ Left ventricular dysfunction after myocardial infarction
Adults: 6.25 mg P.O. as a test dose, followed by 12.5 mg t.i.d. May increase up to 50 mg t.i.d.
➣ Diabetic nephropathy
Adults: 25 mg P.O. t.i.d.
• Renal impairment
• Bartter's syndrome
• Hypertension associated with scleroderma
• Management of hypertensive crisis
• Raynaud's syndrome
• Rheumatoid arthritis
• Severe childhood hypertension
• Hypersensitivity to drug or other ACE inhibitors
• Angioedema (hereditary or idiopathic)
Use cautiously in:
• renal or hepatic impairment, hypovolemia, hyponatremia, aortic stenosis and hypertrophic cardiomyopathy, cardiac or cerebrovascular insufficiency, systemic lupus erythematous
• family history of angioedema
• black patients with hypertension
• elderly patients
• breastfeeding patients
• Discontinue other antihypertensives 1 week before starting captopril, if possible.
• Give 1 hour before meals on empty stomach.
CNS: headache, dizziness, drowsiness, fatigue, weakness, insomnia
CV: angina pectoris, tachycardia, hypotension
GI: nausea, diarrhea, anorexia
GU: proteinuria, erectile dysfunction, decreased libido, gynecomastia, renal failure
Hematologic: anemia, agranulocytosis, leukopenia, pancytopenia, thrombocytopenia
Respiratory: cough, asthma, bronchitis, dyspnea, eosinophilic pneumonitis
Skin: rash, angioedema
Other: altered taste, fever
Drug-drug. Allopurinol: increased risk of hypersensitivity reaction
Antacids: decreased captopril absorption Antihypertensives, general anesthetics that lower blood pressure, nitrates, phenothiazines: additive hypotension
Digoxin, lithium: increased blood levels of these drugs, increased risk of toxicity
Epoetin alfa: additive hyperkalemia
Indomethacin: reduced antihypertensive effect of captopril
Nonsteroidal anti-inflammatory drugs: decreased antihypertensive response
Potassium-sparing diuretics, potassium supplements: hyperkalemia
Probenecid: decreased elimination and increased blood level of captopril
Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, blood urea nitrogen, creatinine, potassium: increased levels
Granulocytes, hemoglobin, platelets, red blood cells, sodium, white blood cells: decreased levels
Urine acetone: false-positive result
Drug-food. Any food: decreased captopril absorption
Salt substitutes containing potassium: hyperkalemia
Drug-herbs. Capsaicin, yohimbine: cough
Drug-behaviors. Acute alcohol ingestion: additive hypotension
☞ Monitor for sudden blood pressure drop within 3 hours of initial dose if patient is receiving concurrent diuretics and on a low-sodium diet.
• Monitor hematologic, kidney, and liver function test results.
• Check for proteinuria monthly and after first 9 months of therapy.
• Tell patient to take drug 1 hour before meals on empty stomach.
• Advise patient to report fever, rash, sore throat, mouth sores, fast or irregular heartbeat, chest pain, or cough.
• Inform patient that dizziness, fainting, and light-headedness usually disappear once his body adjusts to drug.
• Tell patient his ability to taste may decrease during first 2 to 3 months of therapy.
• Caution patient to avoid over-the-counter medications unless approved by prescriber.
• 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.