telmisartan

Telmisartan is an angiotensin II receptor blocker (ARB) used to treat hypertension and to reduce cardiovascular risk in certain patients. It selectively blocks the AT1 receptor, inhibiting the vasoconstrictive and aldosterone-secreting effects of angiotensin II. By blocking these pathways, telmisartan lowers blood pressure and decreases sympathetic activity and vascular remodeling. Unlike ACE inhibitors, it does not increase bradykinin levels, so the incidence of cough is lower.

Medical uses include the management of hypertension. Telmisartan is also used in some patients to reduce proteinuria and protect renal function in type 2 diabetes, and it may be employed in patients who are intolerant to ACE inhibitors.

Administration and dosing: telmisartan is taken orally, with or without food. The typical starting dose for hypertension is 40 mg once daily, with a usual maintenance range of 40–80 mg once daily. Dosing may be adjusted based on blood pressure response and patient tolerance.

Pharmacokinetics: telmisartan has a long duration of action, allowing once-daily dosing. It is highly bound to plasma proteins and undergoes glucuronidation rather than extensive cytochrome P450 metabolism. Excretion occurs primarily via bile and feces, with minimal renal clearance.

Adverse effects and safety: common side effects include dizziness, upper respiratory infections, back pain, and fatigue. Hyperkalemia can occur, especially in patients with renal impairment or those taking potassium supplements. Rare but serious adverse effects include angioedema. Telmisartan is contraindicated in pregnancy; use is cautioned in renal or hepatic impairment and in conditions predisposing to hyperkalemia.

Interactions: NSAIDs may reduce antihypertensive effects; concomitant potassium-sparing diuretics or other RAAS inhibitors can increase the risk of hyperkalemia; monitor for drug interactions with lithium and other agents. Telmisartan is marketed under brand names such as Micardis and is also available as a generic.