A triple-drug, fixed-dose combination (FDC) antihypertensive medication containing an angiotensin II receptor blocker (ARB), a dihydropyridine calcium channel blocker (CCB), and a thiazide diuretic. It is indicated for the treatment of essential hypertension in patients whose blood pressure is not adequately controlled on any two of the following antihypertensive classes: ARBs, CCBs, and thiazide diuretics. This combination provides synergistic blood pressure lowering through complementary mechanisms, often allowing for lower doses of individual components and improved adherence.
Adult: One tablet (Olmesartan 40mg/Amlodipine 5mg/Hydrochlorothiazide 12.5mg) once daily. Dose may be titrated after 2-4 weeks based on response. Not for initial therapy.
Note: Can be taken with or without food. Administer orally, preferably at the same time each day, with a glass of water. Dose should be individualized. Missed dose: Take as soon as remembered, but skip if it's almost time for the next dose. Do not double dose.
This combination exerts a multi-pronged antihypertensive effect. Olmesartan selectively blocks the binding of angiotensin II to the AT1 receptor, inhibiting its vasoconstrictive and aldosterone-secreting effects. Amlodipine inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle, causing peripheral arterial vasodilation. Hydrochlorothiazide inhibits sodium reabsorption in the distal convoluted tubule, increasing excretion of sodium, chloride, and water, reducing plasma volume.
Pregnancy: CONTRANDICATED in second and third trimesters (Pregnancy Category D). Olmesartan can cause injury and death to the developing fetus, including oligohydramnios, renal failure, skull hypoplasia, and death. Discontinue as soon as pregnancy is detected. First trimester use should be avoided unless absolutely necessary.
Driving: Caution advised, especially during initiation and dose adjustment, due to potential dizziness, lightheadedness, or fatigue.
| Other Antihypertensives (e.g., ACEi, beta-blockers) | Additive hypotensive effect. Risk of severe hypotension. | Major |
| Potassium-sparing diuretics (e.g., spironolactone, amiloride) / Potassium supplements | Increased risk of hyperkalemia (olmesartan effect). | Major |
| NSAIDs (e.g., ibuprofen, diclofenac) | May reduce antihypertensive effect, increase risk of renal impairment, and antagonize diuretic effect. | Major |
| Lithium | Thiazides reduce renal clearance of lithium, increasing risk of lithium toxicity. | Major |
| CYP3A4 Inhibitors (e.g., ketoconazole, itraconazole, ritonavir, clarithromycin, grapefruit juice) | Increase amlodipine plasma concentration, risk of hypotension and edema. | Moderate |
| CYP3A4 Inducers (e.g., rifampicin, carbamazepine, phenytoin) | Decrease amlodipine plasma concentration, reducing efficacy. | Moderate |
| Corticosteroids (e.g., prednisolone) | Antagonize hypokalemic and hypotensive effects of thiazide. | Moderate |
| Antidiabetic drugs (Insulin, Sulfonylureas) | Thiazide may decrease glucose tolerance, requiring dose adjustment. | Moderate |
| Colestipol/Cholestyramine | May reduce absorption of hydrochlorothiazide. | Moderate |
| Allopurinol | Increased risk of hypersensitivity reactions when combined with thiazides. | Moderate |
| Alcohol, Barbiturates, Narcotics | Potentiation of orthostatic hypotension. | Moderate |
| Digoxin | Hypokalemia/hypomagnesemia from thiazide may predispose to digitalis toxicity. | Moderate |
Same composition (Olmesartan Medoxomil (40mg) + Amlodipine (5mg) + Hydrochlorothiazide (12.5mg)), different brands: