A fixed-dose combination (FDC) antihypertensive medication containing an angiotensin II receptor blocker (ARB), Losartan, and a dihydropyridine calcium channel blocker (CCB), Amlodipine. This combination provides synergistic blood pressure control by blocking the renin-angiotensin-aldosterone system (RAAS) and inhibiting calcium influx into vascular smooth muscle, leading to vasodilation. It is a first-line therapy for hypertension, especially in patients requiring more than one drug to achieve target BP, and is widely used in the Indian population due to its efficacy, tolerability, and once-daily dosing.
Adult: One tablet (Losartan 50mg/Amlodipine 5mg) once daily. Dose may be titrated after 2-4 weeks based on response. Maximum: Losartan 100mg / Amlodipine 10mg per day, typically as separate components or higher strength FDC.
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. Do not crush or chew.
The combination exerts a dual mechanism for vasodilation and blood pressure reduction. Losartan selectively and competitively antagonizes the binding of angiotensin II to the AT1 receptor subtype, blocking its vasoconstrictor and aldosterone-secreting effects. Amlodipine inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle, leading to peripheral arterial vasodilation and reduced peripheral vascular resistance. The combination results in additive/synergistic antihypertensive effects with a potentially lower incidence of edema compared to Amlodipine monotherapy.
Pregnancy: CONTRANDICATED in second and third trimester. Drug exposure during the second and third trimesters can cause injury and even death to the developing fetus (oligohydramnios, renal failure, skull hypoplasia, hypotension). Discontinue as soon as pregnancy is detected. Category D (US FDA).
Driving: May cause dizziness, lightheadedness, or fatigue, especially during initiation of therapy or dose escalation. Patients should be cautioned about operating machinery or driving until they know how the medication affects them.
| Potassium supplements / Potassium-sparing diuretics (Spironolactone, Amiloride) | Increased risk of hyperkalemia. | Major |
| Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) e.g., Ibuprofen, Diclofenac | May reduce antihypertensive effect and increase risk of renal impairment and hyperkalemia. | Major |
| Other antihypertensives (Diuretics, Beta-blockers, ACE inhibitors) | Additive hypotensive effect. | Moderate |
| Lithium | Losartan may decrease lithium excretion, increasing lithium toxicity risk. | Major |
| Strong CYP3A4 inhibitors (Ketoconazole, Itraconazole, Clarithromycin, Ritonavir) | May increase Amlodipine plasma concentration, increasing risk of side effects like edema and hypotension. | Moderate |
| Simvastatin | Amlodipine may increase simvastatin exposure, slightly increasing risk of myopathy. Limit simvastatin dose to 20mg daily. | Moderate |
| Sildenafil, Tadalafil (PDE5 inhibitors) | Additive vasodilatory effect, risk of severe hypotension. | Major |