Telmisartan

• Hypertension
• Cardiovascular Disease Prevention
• Diabetic Nephropathy

Telmisartan is an angiotensin II receptor blocker (ARB) used to treat hypertension and reduce cardiovascular risk in high-risk patients. It has the longest half-life among ARBs, providing sustained 24-hour blood pressure control, and demonstrates unique PPAR-gamma activating properties that may offer metabolic benefits.

Mechanism of Action

Telmisartan lowers blood pressure through receptor blockade and additional mechanisms:

• AT1 receptor blockade: Selectively blocks angiotensin II type 1 receptors
• Prevents vasoconstriction: Blocks angiotensin II-induced arterial smooth muscle contraction
• Reduces aldosterone secretion: Decreases sodium and water retention
• PPAR-gamma activation: Partial agonist activity may improve insulin sensitivity and lipid profiles
• Long duration: 24-hour half-life provides consistent BP control

Unlike ACE inhibitors, telmisartan does not affect bradykinin metabolism, resulting in a lower incidence of cough.

Available Formulations

Telmisartan is available as oral tablets:

• 20 mg tablets
• 40 mg tablets
• 80 mg tablets (Micardis)
• Combination products with hydrochlorothiazide (Micardis HCT) and amlodipine (Twynsta)

Medical Uses

FDA-Approved Indications:

• Treatment of hypertension (alone or with other antihypertensives)
• Cardiovascular risk reduction in patients 55 years and older at high risk for major cardiovascular events who are unable to take ACE inhibitors

Dosing Guidelines

Hypertension:

• Initial: 40 mg once daily
• Maintenance: 20-80 mg once daily
• Most patients respond to 40-80 mg daily

Cardiovascular Risk Reduction:

• 80 mg once daily

Administration:

• Take with or without food
• Can be taken at any time of day; evening dosing may optimize nocturnal BP control

Important Safety Information

Black Box Warning:

• Fetal toxicity: Discontinue as soon as pregnancy is detected; drugs that act on the renin-angiotensin system can cause fetal injury and death

Contraindications:

• Known hypersensitivity to telmisartan
• Concomitant use with aliskiren in patients with diabetes
• Pregnancy

Warnings and Precautions:

• Hypotension: May occur in volume-depleted patients; correct volume depletion before initiating
• Hyperkalemia: Risk increased with renal impairment, diabetes, or potassium supplements
• Renal function deterioration: May occur in patients with renal artery stenosis
• Hepatic impairment: Start with lower doses; titrate slowly

Drug Interactions

• Aliskiren: Contraindicated in diabetic patients; avoid in patients with GFR <60 mL/min
• ACE inhibitors: Avoid dual RAAS blockade due to increased risks
• Potassium-sparing diuretics/potassium supplements: Increased hyperkalemia risk
• NSAIDs: May reduce antihypertensive effect and worsen renal function
• Lithium: Increased lithium levels; monitor closely
• Digoxin: May increase digoxin levels by 20%; monitor
• Ramipril: Absorption of ramipril reduced when given with telmisartan

Special Populations

• Renal Impairment: No dose adjustment needed; monitor potassium and renal function
• Hepatic Impairment: Start with 20 mg daily; increase slowly in mild to moderate impairment; use with caution
• Elderly: No dose adjustment needed; monitor for hypotension
• Pregnancy: Contraindicated; discontinue immediately if pregnancy occurs
• Lactation: Not recommended; unknown if excreted in breast milk
• Pediatric: Safety and efficacy not established in children