Telmisartan + Hydrochlorothiazide

Telmisartan is an angiotensin II receptor blocker (ARB) that selectively blocks the AT1 receptor, preventing angiotensin II from binding and exerting its vasoconstrictor and aldosterone-secreting effects. This leads to vasodilation, reduced systemic vascular resistance, and decreased blood pressure. Hydrochlorothiazide is a thiazide diuretic that inhibits the reabsorption of sodium and chloride ions in the distal convoluted tubule, leading to increased excretion of sodium, chloride, and water, thereby reducing plasma volume and blood pressure. The combination provides additive antihypertensive effects and the ARB helps to counteract the potassium-wasting effect and sympathetic activation induced by the diuretic. Combination rationale: The combination of Telmisartan and Hydrochlorothiazide offers complementary mechanisms of action, providing synergistic blood pressure reduction often superior to either agent alone. Telmisartan effectively blocks the renin-angiotensin-aldosterone system, while Hydrochlorothiazide enhances sodium and water excretion. This FDC improves patient compliance due to fewer pills and is particularly useful when monotherapy fails to achieve target blood pressure.

Adult

Initial: Telmisartan 40 mg/Hydrochlorothiazide 12.5 mg orally once daily. If blood pressure remains uncontrolled after 2-4 weeks, the dose may be increased to Telmisartan 80 mg/Hydrochlorothiazide 12.5 mg or Telmisartan 80 mg/Hydrochlorothiazide 25 mg once daily. Common strengths available in India are Telmisartan 40mg/HCTZ 12.5mg, Telmisartan 80mg/HCTZ 12.5mg, and Telmisartan 80mg/HCTZ 25mg.

Pediatric

Safety and efficacy in children and adolescents below 18 years of age have not been established. Therefore, use in pediatric patients is not recommended and is generally contraindicated.

Renal adjustment

Contraindicated in severe renal impairment (creatinine clearance <30 mL/min) due to the hydrochlorothiazide component. For patients with mild to moderate renal impairment (creatinine clearance 30-80 mL/min), no initial dose adjustment is generally needed, but close monitoring of renal function and electrolytes is recommended.

Hepatic adjustment

Contraindicated in severe hepatic impairment, biliary obstructive disorders. For mild to moderate hepatic impairment, dose adjustment may be necessary for telmisartan, with a maximum dose of 40 mg telmisartan once daily for telmisartan monotherapy. Use of the FDC is not recommended in these patients unless strictly necessary and with close monitoring.

Geriatric

No dosage adjustment is generally required based solely on age. However, caution is advised, and monitoring of renal function and electrolytes is important, especially in elderly patients with potential underlying renal impairment. Starting with a lower dose may be prudent.

Max dose

Telmisartan 80 mg/Hydrochlorothiazide 25 mg once daily.

• Hypersensitivity to telmisartan, hydrochlorothiazide, or any sulfonamide-derived drugs. Severe hepatic impairment, biliary obstructive disorders, or anuria. Severe renal impairment (creatinine clearance <30 mL/min). Refractory hypokalemia, hyponatremia, hypercalcemia, and symptomatic hyperuricemia. Second and third trimesters of pregnancy. Concomitant use with aliskiren in patients with diabetes mellitus or renal impairment (GFR <60 mL/min/1.73 m2).