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captopril
Acenorm‡, Capoten, Enzace‡, Novo-Captoril†

Pregnancy Risk Category C (D in second and third trimesters)

How supplied
Tablets:
12.5 mg, 25 mg, 50 mg, 100 mg

Action
Not clearly defined. Thought to inhibit ACE, preventing conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. Reduced formation of angiotensin II decreases peripheral arterial resistance, thus decreasing aldosterone secretion, thereby reducing sodium and water retention and lowering blood pressure.

Indications & dosage
Hypertension
--
Adults:
25 mg P.O. b.i.d. or t.i.d. initially. If blood pressure isn't satisfactorily controlled in 1 to 2 weeks, increase dosage to 50 mg b.i.d. or t.i.d. If not satisfactorily controlled after another 1 to 2 weeks, expect a diuretic to be added. If further blood pressure reduction is needed, dosage may be raised to 150 mg t.i.d. while continuing diuretic. Maximum daily dose is 450 mg.
Heart failure, to reduce risk of death and to slow development of heart failure after MI
--
Adults:
initially, 6.25 to 12.5 mg P.O. t.i.d. Gradually increased to 50 mg t.i.d., p.r.n. Maximum daily dose is 450 mg.
Diabetic nephropathy
--
Adults:
25 mg P.O. t.i.d.

Adverse reactions
CNS:
dizziness, fainting, headache, malaise, fatigue.
CV:
tachycardia, hypotension, angina pectoris.
GI:
abdominal pain, anorexia, constipation, diarrhea, dry mouth, dysgeusia, nausea, vomiting.
Hematologic:
leukopenia, agranulocytosis, pancytopenia, anemia, thrombocytopenia.
Hepatic:
transient increase in hepatic enzymes.
Metabolic:
hyperkalemia.
Respiratory:
dyspnea, dry, persistent, nonproductive cough.
Skin:
urticarial rash, maculopapular rash, pruritus, alopecia.
Other:
fever, angioedema of face and extremities.

Interactions
Drug-drug.
Antacids: decreased captopril effect. Separate administration times.
Digoxin:
may increase serum digoxin level by 15% to 30%. Monitor closely.
Diuretics, other antihypertensives:
risk of excessive hypotension. Diuretic may need to be discontinued or captopril dosage lowered.
Insulin, oral antidiabetics:
risk of hypoglycemia when captopril therapy is initiated. Monitor closely.
Lithium:
increased lithium levels and symptoms of toxicity possible. Monitor patient closely.
NSAIDs:
may reduce antihypertensive effect. Monitor blood pressure.
Potassium-sparing diuretics, potassium supplements:
increased risk of hyperkalemia. Avoid these drugs unless hypokalemic blood levels are confirmed.
Drug-herb.
Black catechu: additional hypotensive effect. Avoid concomitant use.
Drug-food.
Salt substitutes containing potassium: risk of hyperkalemia. Monitor closely.

Effects on diagnostic tests
Drug may cause false-positive results for urinary acetone.

Contraindications
Contraindicated in patients with hypersensitivity to drug or other ACE inhibitors.

Nursing considerations

Patient teaching

*Liquid contains alcohol. **May contain tartrazine.  †Canada  ‡Australia  §U.K.  OTCOver the counter
Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE-THREATENING

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