A fixed-dose combination (FDC) antihypertensive medication containing an ACE inhibitor (Enalapril) and a thiazide diuretic (Hydrochlorothiazide). It provides synergistic blood pressure lowering by reducing peripheral vascular resistance and decreasing plasma volume. This combination is widely used in the Indian market for the management of essential hypertension, especially in patients requiring more than one drug for adequate control.
Adult: One tablet (Enalapril 5mg + HCTZ 12.5mg) once daily. Dose may be titrated up to a maximum of Enalapril 20mg + HCTZ 25mg per day based on response. Usually administered in the morning.
Note: Take orally, with or without food. Take in the morning to avoid nocturia. Swallow whole with a glass of water. Do not skip doses. If a dose is missed, take it as soon as remembered unless it is almost time for the next dose.
Enalapril inhibits the Angiotensin Converting Enzyme (ACE), preventing the conversion of angiotensin I to angiotensin II (a potent vasoconstrictor). This leads to vasodilation, reduced aldosterone secretion (causing mild potassium retention), and decreased peripheral vascular resistance. Hydrochlorothiazide inhibits sodium reabsorption in the distal convoluted tubule of the nephron, promoting excretion of sodium, chloride, and water, thereby reducing plasma volume and extracellular fluid volume. The combination results in additive antihypertensive effects.
Pregnancy: CONTRANDICATED in second and third trimesters (ACE inhibitors can cause fetal injury and death: oligohydramnios, fetal hypocalvaria, renal failure, lung hypoplasia). Discontinue as soon as pregnancy is detected. Category D (US FDA).
Driving: May cause dizziness, lightheadedness, or fatigue, especially during initiation of therapy. Patients should be cautioned about operating machinery or driving until they know how the medication affects them.
| Lithium | HCTZ reduces renal clearance of lithium, increasing risk of lithium toxicity. | Major |
| NSAIDs (e.g., Ibuprofen, Diclofenac) | May reduce antihypertensive effect and increase risk of renal impairment. | Major |
| Potassium supplements / Potassium-sparing diuretics (e.g., Spironolactone) | Increased risk of hyperkalemia with Enalapril. | Major |
| Other Antihypertensives / Vasodilators | Additive hypotensive effect. | Moderate |
| Antidiabetic drugs (Insulin, Sulfonylureas) | HCTZ may decrease glucose tolerance, requiring dose adjustment. | Moderate |
| Allopurinol | Increased risk of hypersensitivity reactions. | Moderate |
| Cholestyramine / Colestipol | May reduce absorption of HCTZ. | Moderate |
| Digoxin | Hypokalemia or hypomagnesemia from HCTZ may predispose to digitalis toxicity. | Moderate |
Same composition (Enalapril (5mg) + Hydrochlorothiazide (12.5mg)), different brands: