1. Clinical Overview
Ramipril is a long-acting, non-sulfhydryl angiotensin-converting enzyme (ACE) inhibitor prodrug. It is hydrolyzed to its active metabolite, ramiprilat, which inhibits the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. This leads to vasodilation, reduced aldosterone secretion, and decreased sodium and water retention. It is a cornerstone therapy for hypertension, heart failure, and post-myocardial infarction management in the Indian population, with the 1.25mg strength often used for initiation, dose titration, or in patients with renal impairment.
| Onset | Duration | Bioavailability |
|---|---|---|
| Within 1-2 hours after oral administration. | Approximately 24 hours, supporting once-daily dosing. | Approximately 50-60% for the parent drug. Bioavailability of the active metabolite ramiprilat is lower (about 45%). |
2. Mechanism of Action
Ramipril is a prodrug hydrolyzed by hepatic esterases to its active metabolite, ramiprilat. Ramiprilat competitively inhibits angiotensin-converting enzyme (ACE or kininase II). This inhibition prevents the conversion of angiotensin I to the potent vasoconstrictor angiotensin II and decreases the degradation of bradykinin, a potent vasodilator. The net effect is decreased systemic vascular resistance (afterload), decreased aldosterone secretion (reducing sodium/water retention), and increased vasodilation.
3. Indications & Uses
- Hypertension (essential or renovascular)
- Congestive Heart Failure (post-MI or reduced ejection fraction)
- Post-Myocardial Infarction (to reduce risk of death, MI, or stroke in clinically stable patients)
- Reduction in risk of MI, stroke, or death from cardiovascular causes in high-risk patients (aged 55+ with history of CAD, stroke, PVD, or diabetes with one other CV risk factor)
4. Dosage & Administration
Adult Dosage: Hypertension: Initial 1.25-2.5 mg once daily; maintenance 2.5-10 mg once daily. Heart Failure/Post-MI: Initiate at 1.25 mg twice daily; titrate to target of 5 mg twice daily. High CV Risk: Initial 2.5 mg once daily; titrate to 10 mg once daily.
Administration: Can be taken with or without food. Swallow whole with a glass of water. For patients with difficulty swallowing, the capsule can be opened and the contents sprinkled on a small amount (tablespoon) of apple sauce or mixed in a glass of water or apple juice; consume immediately. Do not crush or chew the pellets. Dose timing should be consistent daily.
5. Side Effects
Common side effects may include:
- Persistent dry, non-productive cough
- Dizziness, lightheadedness (especially with initial doses)
- Headache
- Fatigue
- Nausea
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Diuretics (especially loop and thiazide) | Potentiates hypotensive effect; risk of first-dose hypotension. | Major |
| Potassium-sparing diuretics (Spironolactone, Amiloride) | Increased risk of severe hyperkalemia. | Major |
| Potassium supplements/Salt substitutes | Increased risk of hyperkalemia. | Major |
| Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) e.g., Ibuprofen, Diclofenac | May diminish antihypertensive effect and increase risk of renal impairment. | Moderate |
| Lithium | Increased serum lithium levels and toxicity. | Major |
| Aliskiren | Increased risk of hyperkalemia, hypotension, and renal impairment (contraindicated in diabetes/renal impairment). | Major |
| Antidiabetics (Insulin, Sulfonylureas) | May enhance hypoglycemic effect. | Moderate |
| Allopurinol, Procainamide, Immunosuppressants | Increased risk of hypersensitivity reactions, including Stevens-Johnson Syndrome. | Moderate |
7. Patient Counselling
- DO take your medication at the same time each day.
- DO inform all your doctors and dentists you are on Ramipril.
- DO get regular blood tests (creatinine, potassium) as advised by your doctor.
- DONT stop taking the medicine suddenly without consulting your doctor.
- DONT use potassium supplements or salt substitutes without medical advice.
- DONT take over-the-counter NSAIDs (like ibuprofen) for pain/fever without consulting your doctor.
8. Toxicology & Storage
Overdose: Profound hypotension, which may lead to circulatory shock, bradycardia, electrolyte disturbances (hyperkalemia), and acute renal failure. Symptoms include dizziness, lightheadedness, fainting, and weakness.
Storage: Store below 30°C. Protect from light and moisture. Keep the container tightly closed. Keep out of reach of children. Do not use after the expiry date printed on the pack.