Lisinopril is a long-acting, orally active, non-sulfhydryl angiotensin-converting enzyme (ACE) inhibitor. It is a lysine derivative of enalaprilat and is used primarily for the treatment of hypertension, heart failure, and to improve survival after myocardial infarction. It is a first-line antihypertensive agent in the Indian population, effective in both low-renin and high-renin hypertension.
Adult: Hypertension: Initial dose 2.5-5 mg once daily, usual maintenance 10-20 mg once daily, max 40 mg/day. Heart Failure: Start at 2.5 mg once daily under close medical supervision, titrate to target of 20-35 mg once daily. Post-MI: Start 5 mg within 24 hours, then 5 mg after 24 hours, 10 mg after 48 hours, then 10 mg once daily for 6 weeks.
Note: Can be taken with or without food. Should be taken at the same time each day, preferably in the morning. Tablet should be swallowed whole with a glass of water. For heart failure patients, initiate under close supervision, often starting in-hospital or with frequent monitoring for hypotension.
Lisinopril competitively inhibits angiotensin-converting enzyme (ACE or kininase II). This inhibition prevents the conversion of angiotensin I to the potent vasoconstrictor angiotensin II. The resulting decrease in angiotensin II leads to decreased vasoconstriction, reduced aldosterone secretion (leading to sodium and water excretion), and increased plasma renin activity. It also inhibits the degradation of bradykinin, a potent vasodilator, contributing to its hypotensive effect.
Pregnancy: Pregnancy Category D (US FDA). Contraindicated in second and third trimester. Can cause fetal injury and death, including hypotension, neonatal skull hypoplasia, anuria, reversible or irreversible renal failure, and oligohydramnios. Discontinue as soon as pregnancy is detected.
Driving: May cause dizziness, lightheadedness, or fatigue, especially during initiation or dose escalation. Patients should not drive or operate machinery until they know how the medication affects them.
| Diuretics (especially potent loop diuretics like Furosemide) | Potentiates hypotensive effect; risk of first-dose hypotension. May cause excessive reduction in blood pressure. | Major |
| Potassium-sparing diuretics (Spironolactone, Amiloride), Potassium supplements, Salt substitutes | Increased risk of severe hyperkalemia. | Major |
| Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) like Ibuprofen, Diclofenac | May diminish antihypertensive effect and increase risk of renal impairment, especially in elderly or volume-depleted. | Moderate |
| Lithium | Lisinopril decreases lithium excretion, increasing risk of lithium toxicity. | Major |
| Antidiabetic agents (Insulin, Sulfonylureas) | May enhance hypoglycemic effect; monitor blood glucose. | Moderate |
| Aliskiren | Increased risk of hyperkalemia, hypotension, and renal impairment (contraindicated in diabetes and renal impairment). | Major |
| Gold injections (Sodium aurothiomalate) | May cause nitritoid reactions (flushing, nausea, hypotension). | Moderate |