Capoten (captopril) is an angiotensin-converting enzyme (ACE) inhibitor indicated for the management of hypertension, heart failure, and post-myocardial infarction left ventricular dysfunction. As a foundational therapy in cardiovascular medicine, it works by inhibiting the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, thereby reducing peripheral arterial resistance and decreasing blood pressure. Its well-established efficacy and extensive clinical history make it a trusted option for physicians seeking to optimize cardiovascular outcomes in appropriate patient populations. This product card provides a comprehensive, evidence-based overview for healthcare professionals.

Features

• Active ingredient: Captopril
• Drug class: Angiotensin-converting enzyme (ACE) inhibitor
• Available formulations: Oral tablets (12.5 mg, 25 mg, 50 mg, 100 mg)
• Onset of action: 15–60 minutes after oral administration
• Peak effect: 60–90 minutes post-dose
• Duration of action: Dose-dependent, typically 6–12 hours
• Bioavailability: Approximately 60–75%
• Protein binding: 25–30%
• Metabolism: Hepatic (minimal)
• Elimination half-life: <2 hours (prolonged in renal impairment)
• Excretion: Primarily renal (40–50% as unchanged drug)

Benefits

• Effectively lowers blood pressure by reducing systemic vascular resistance
• Improves survival and functional status in patients with congestive heart failure
• Reduces afterload and preload, decreasing myocardial oxygen demand
• Provides renal protective effects in diabetic nephropathy by reducing intraglomerular pressure
• Demonstrates proven mortality benefit in post-MI patients with left ventricular dysfunction
• Offers flexible dosing regimen adaptable to individual patient response and tolerability

Common use

Capoten is primarily prescribed for the treatment of hypertension, either as monotherapy or in combination with other antihypertensive agents. It is also indicated for the management of heart failure when conventional therapy with diuretics and digitalis proves insufficient. Additionally, it is used to improve survival following myocardial infarction in clinically stable patients with left ventricular dysfunction (ejection fraction ≤40%). Off-label uses include the management of diabetic nephropathy and scleroderma renal crisis, though these applications require careful clinical judgment and monitoring.

Dosage and direction

Dosage must be individualized based on clinical response and tolerability. For hypertension: Initial dose is 25 mg twice daily; may be increased to 50 mg twice daily after 1–2 weeks. Maintenance dose typically ranges from 25–150 mg twice daily. Maximum dose: 450 mg/day. For heart failure: Initial dose is 6.25–12.5 mg three times daily; titrate upward to target maintenance dose of 50–100 mg three times daily as tolerated. For post-MI left ventricular dysfunction: Initiate therapy at 6.25 mg followed by 12.5 mg three times daily, increasing to 50 mg three times daily over several weeks. Administer at least one hour before meals for optimal absorption.

Precautions

Monitor blood pressure closely during initial dosing and titration periods. Assess renal function and serum potassium before initiation and periodically during therapy. Use with caution in patients with renal impairment, collagen vascular diseases, or those taking diuretics. May cause hypotension, especially in volume-depleted patients. Avoid use in pregnancy due to potential fetal harm. Counsel patients about the possibility of cough and angioedema. Regular monitoring of hematologic parameters is advised in patients with autoimmune diseases or renal impairment.

Contraindications

History of angioedema related to previous ACE inhibitor therapy. Hypersensitivity to captopril or any component of the formulation. Concomitant use with aliskiren in patients with diabetes. Bilateral renal artery stenosis or stenosis in a solitary kidney. Second and third trimester of pregnancy.

Possible side effect

Common adverse reactions include cough (5–20%), rash (4–7%), taste disturbance (2–4%), and hypotension (2–4%). Less frequent effects include hyperkalemia, renal impairment, angioedema (0.1–0.5%), and neutropenia/agranulocytosis (rare). Gastrointestinal disturbances such as nausea and diarrhea may occur. Proteinuria has been reported in approximately 1% of patients. Most side effects are dose-dependent and may diminish with continued therapy or dose reduction.

Drug interaction

Potassium supplements or potassium-sparing diuretics may increase risk of hyperkalemia. NSAIDs may diminish antihypertensive effect and increase risk of renal impairment. Diuretics may potentiate hypotensive effect. Lithium levels may increase with concomitant use. Enhanced hypotensive effect with other antihypertensive agents. Reduced absorption with antacids (administer at least 2 hours apart). Increased risk of hypoglycemia with insulin or oral hypoglycemic agents.

Missed dose

If a dose is missed, it should be taken as soon as possible. However, if it is nearly time for the next dose, the missed dose should be skipped. Patients should not double the dose to make up for a missed administration. Consistent dosing is important for maintaining stable blood pressure control, but occasional missed doses are unlikely to cause significant clinical consequences in most patients.

Overdose

Symptoms may include profound hypotension, bradycardia, circulatory shock, electrolyte disturbances, and renal failure. Management involves supportive care with volume expansion with normal saline. Hemodialysis may be effective due to captopril’s relatively low molecular weight and partial renal excretion. Bradycardia may require atropine administration. Vasopressors may be necessary in cases of severe hypotension unresponsive to volume expansion.

Storage

Store at controlled room temperature (20–25°C or 68–77°F). Protect from moisture and light. Keep in original container with tight closure. Do not use if tablets show signs of discoloration or deterioration. Keep out of reach of children and pets. Do not transfer to other containers that may not provide adequate protection from light and moisture.

Disclaimer

This information is intended for healthcare professionals and should not replace clinical judgment. Prescribers should consult full prescribing information before initiating therapy. Dosage and administration must be individualized based on patient characteristics and clinical situation. Safety and effectiveness in pediatric patients have not been established. Patients should be advised to read the patient information leaflet and discuss any concerns with their healthcare provider.

Reviews

Clinical trials demonstrate Capoten’s efficacy in reducing blood pressure by 10–15 mmHg systolic and 5–10 mmHg diastolic in hypertensive patients. In heart failure studies, it has shown significant improvement in exercise tolerance and reduction in hospitalization rates. The SAVE trial established its mortality benefit in post-MI patients with left ventricular dysfunction. Most real-world evidence supports its position as a well-tolerated and effective ACE inhibitor, though cough remains a frequent reason for discontinuation. Many clinicians appreciate its relatively short half-life, which allows for rapid dose titration and management of adverse effects.