Classifications: angiotensin-converting enzyme (ace) inhibitor; antihypertensive agent; Therapeutic: antihypertensive agent; ace inhibitor
Pregnancy Category: C first trimester; D second and third trimester
12.5 mg, 25 mg, 50 mg, 100 mg tablets
Lowers blood pressure by specific inhibition of the angiotensin-converting enzyme (ACE). This interrupts conversion sequences
initiated by renin that lead to formation of angiotensin II, a potent vasoconstrictor. ACE inhibition alters hemodynamics
without compensatory reflex tachycardia or changes in cardiac output (except in patients with CHF). Peripheral vascular resistance
is lowered by vasodilation. Inhibition of ACE also leads to decreased circulating aldosterone. In heart failure, captopril
administration is followed by a fall in CVP and pulmonary wedge pressure; hypotensive action appears to be unrelated to
plasma renin levels.
Effective in stepped protocol management of hypertension to convert to normotensive range, and in congestive heart failure
with resulting decreases in dyspnea and improved exercise tolerance.
Hypertension; CHF (with digitalis and diuretics), diabetic nephropathy, left ventricular dysfunction post MI.
Angioedema, hypersensitivity to captopril or ACE inhibitors; hypotension; pregnancy (catetory C first trimester and category
D second and third trimester), lactation.
Impaired renal function, patient with solitary kidney; collagen-vascular diseases (scleroderma, SLE); patients receiving
IMMUNOSUPPRESSANTS or other drugs that cause leukopenia or agranulocytosis; autoimmune disease, bone marrow suppression, coronary or cerebrovascular
disease; cardiomyopathy, aortic stenosis; severe salt/volume depletion; heart failure, renal artery stenosis, renal disease,
renal failure, renal impairment; hyperkalemia, elderly.
Route & Dosage
Adult: PO 6.2525 mg t.i.d., may increase to 50 mg t.i.d. (max: 450 mg/d)
Child: PO 0.312.5 mg/kg q1224h, may titrate up to max of 6 mg/kg/d in 24 divided doses
Infant: PO 0.150.3 mg/kg, may titrate up to 6 mg/kg/d in 14 divided doses
Neonate: PO 0.050.1 mg/kg q824h, may titrate up to 0.5 mg/kg q624h
Premature infant: PO 0.01 mg/kg q812h
Congestive Heart Failure
Adult: PO 6.2512.5 mg t.i.d., may increase to 100 mg t.i.d. (max: 450 mg/d)
Clcr 1050 mL/min: 75% of dose; <10 mL/min: 50% of dose
- Give captopril 1 h before meals. Food reduces absorption by 3040%.
- Store in light-resistant containers at no more than 30° C (86° F) unless otherwise directed.
Adverse Effects (≥1%) Body as a Whole:
Hypersensitivity reactions, serum sickness-like reaction, arthralgia, skin eruptions. CV:
Slight increase in heart rate, first dose hypotension, dizziness, fainting. GI:
Altered taste sensation (loss of taste perception, persistent salt or metallic taste); weight loss, intestinal angioedema. Hematologic:
Hyperkalemia, neutropenia, agranulocytosis
(rare). Respiratory: Cough. Skin: Maculopapular rash,
urticaria, pruritus, angioedema,
Azotemia, impaired renal
function, nephrotic syndrome, membranous glomerulonephritis. Other:
Positive antinuclear antibody (ANA) titers.
Diagnostic Test Interference
Elevated urine protein levels may persist even after captopril has been discontinued. Possibility of transient elevations of BUN and serum creatinine, slight increase in serum potassium, and serum prolactin, increases in liver enzymes, and false-positive urine acetone (using sodium nitroprusside reagent). Captopril may decrease fasting blood sugar in the nondiabetic and cause hypoglycemia in the diabetic patient controlled with antidiabetic drug therapy.
, and antihypertensives
enhance hypotensive effects. Aspirin
and other nsaids
may antagonize hypotensive effects. potassium-sparing diuretics
) increase potassium
decreases elimination and increases effects. Food:
Food decreases absorption; take 3060 min before meals.
6075% absorbed; food may decrease absorption 2540%. Onset:
15 min. Peak:
12 h. Duration:
612 h. Distribution:
To all tissues except CNS; crosses placenta. Metabolism:
Some liver metabolism. Elimination:
Primarily in urine; excreted in breast milk.
Assessment & Drug Effects
- Monitor BP closely following the first dose. A sudden exaggerated hypotensive response may occur within 13 h of first
dose, especially in those with high BP or on a diuretic and restricted salt intake.
- Advise bed rest and BP monitoring for the first 3 h after the initial dose.
- Monitor therapeutic effectiveness. At least 2 wk of therapy may be required before full therapeutic effects are achieved.
- Lab tests: Establish baseline urinary protein levels before initiation of therapy and check at monthly intervals for the
first 8 mo of treatment and then periodically thereafter. Perform WBC and differential counts before therapy is begun and
at approximately 2-wk intervals for the first 3 mo of therapy and then periodically thereafter.
Patient & Family Education
- Report to physician without delay the onset of unexplained fever, unusual fatigue, sore mouth or throat, easy bruising or
bleeding (pathognomonic of agranulocytosis).
- Mild skin eruptions are most likely to appear during the first 4 wk of therapy and may be accompanied by fever and eosinophilia.
- Consult physician promptly if vomiting or diarrhea occur.
- Report darkening or crumbling of nailbeds (reversible with dosage reduction).
- Taste impairment occurs in 510% of patients and generally reverses in 23 mo even with continued therapy.
- Use OTC medications only with approval of the physician. Inform surgeon or dentist that captopril is being taken. Alert diabetic
patient that captopril may produce hypoglycemia. Monitor blood glucose and HbA1c closely during first few weeks of therapy.