Ramipril

Overview

Ramipril is an angiotensin-converting enzyme (ACE) inhibitor used primarily in the treatment of hypertension, heart failure, and the prevention of cardiovascular events. It is a prodrug rapidly converted in the liver to its active metabolite, ramiprilat, which exerts potent ACE inhibition. By blocking ACE, ramipril reduces the conversion of angiotensin I to angiotensin II—a vasoconstrictor that also stimulates aldosterone secretion. The result is systemic vasodilation, reduced afterload and preload, and decreased sodium and water retention, ultimately lowering blood pressure and reducing cardiac workload.

Large-scale trials such as the HOPE (Heart Outcomes Prevention Evaluation) study demonstrated that ramipril significantly reduces the risk of myocardial infarction, stroke, and cardiovascular death in high-risk patients, independent of blood pressure lowering. Its benefit is particularly marked in those with diabetes, prior cardiovascular disease, or multiple risk factors.

Ramipril has a long elimination half-life (13–17 hours for ramiprilat), allowing once-daily dosing in most cases. It can be taken with or without food, though consistency helps with adherence. Like other ACE inhibitors, it is generally well tolerated, though cough and hyperkalaemia can occur. Angioedema, while rare, can be life-threatening and requires immediate discontinuation.

Interactions

Ramipril interacts with a number of medicines via effects on potassium balance, renal function, and blood pressure.

• Potassium-sparing diuretics, potassium supplements, salt substitutes: risk of dangerous hyperkalaemia—monitor closely if combination unavoidable.
• Other antihypertensives (e.g., diuretics, beta-blockers, calcium channel blockers): additive hypotension—monitor blood pressure and adjust doses accordingly.
• NSAIDs: may blunt antihypertensive effect and increase risk of renal impairment—use with caution, especially in older adults.
• Diuretics: can potentiate first-dose hypotension, especially loop diuretics or high-dose thiazides—consider reducing diuretic dose before starting ramipril.
• Aliskiren: avoid in diabetic patients due to increased risk of renal impairment, hypotension, hyperkalaemia.
• Lithium: clearance reduced by ACE inhibitors—risk of lithium toxicity; monitor levels carefully.
• Immunosuppressants (e.g., ciclosporin, tacrolimus): increased risk of hyperkalaemia.
• Alcohol: may enhance hypotensive effect—advise moderation.

Patients should keep an updated list of all medicines and over-the-counter products and review them regularly with their clinician or pharmacist.

Overdose / Missed Dose

Missed dose: take as soon as remembered unless it is almost time for the next dose. If so, skip the missed dose and continue as scheduled. Do not double up.

Accidental double dose: may cause dizziness, lightheadedness, or fainting due to low blood pressure. Sit or lie down, hydrate, and seek advice if symptoms persist.

Large overdose: can cause profound hypotension, bradycardia, electrolyte imbalance, and renal failure. Emergency care is required—management includes IV fluids, monitoring of renal function and electrolytes, vasopressors if needed, and symptomatic support. Haemodialysis is not effective for removing ramiprilat.

Always seek immediate help for suspected overdose, especially in children or vulnerable adults.

Storage

• Store at room temperature (≤25–30 °C depending on brand) in a dry place, protected from light and moisture.
• Keep tablets in the original blister until use.
• Keep out of sight and reach of children.
• Do not use after expiry date on packaging.
• Return unused or expired tablets to a pharmacy take-back program; do not dispose in household waste or wastewater.