Micardis (Telmisartan)

Micardis (telmisartan) acts on the renin‑angiotensin‑aldosterone system to control high blood pressure and related cardiovascular conditions.

• Hypertension: reduces systolic and diastolic blood pressure, improving overall cardiovascular control.
• Cardiovascular risk reduction in high‑risk patients: lowers the incidence of myocardial infarction, stroke and cardiovascular death in patients with established risk factors.
• Stroke risk reduction in high‑risk patients: contributes to decreased risk of recurrent stroke when used as part of comprehensive therapy.

• Telmisartan selectively blocks the angiotensin II type 1 (AT₁) receptor, preventing angiotensin II from binding and activating the receptor. This inhibition stops the vasoconstrictive, aldosterone‑secreting and sympathetic‑stimulating actions of angiotensin II, leading to vasodilation, reduced sodium and water retention, and lower peripheral resistance. By maintaining blockade over a 24‑hour period, telmisartan provides consistent antihypertensive effect with once‑daily dosing.

Telmisartan may cause a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Dizziness: sensation of light‑headedness, especially after standing.
• Headache: mild to moderate pain in the head region.
• Fatigue: feeling unusually tired or weak.
• Upper respiratory tract infection: symptoms such as nasal congestion or sore throat.
• Back pain: discomfort in the lower back region.

Serious or Rare Side Effects

• Angioedema: swelling of the face, lips, tongue or airway requiring immediate medical attention.
• Hyperkalemia: elevated blood potassium levels that can affect heart rhythm.
• Acute renal failure: sudden loss of kidney function, indicated by reduced urine output or increased creatinine.
• Hepatic injury: signs of liver damage including jaundice, dark urine or elevated liver enzymes.

When prescribing telmisartan, clinicians should consider several precautionary measures to ensure patient safety.

• Monitor blood pressure: check regularly to assess therapeutic response and avoid hypotension.
• Assess renal function: evaluate serum creatinine and eGFR before initiation and during treatment.
• Check serum potassium: monitor for hyperkalemia, especially when combined with potassium‑sparing agents.
• Use caution in severe hepatic impairment: dose adjustment may be required due to altered metabolism.
• Avoid use in pregnancy: telmisartan is contraindicated due to risk of fetal toxicity.
• Store at below 25°C: keep in the original packaging, protect from moisture and light.

Telmisartan can interact with other medicines, influencing its efficacy or safety profile.

Major Interactions (Avoid)

• Concomitant use with aliskiren in diabetic patients: increased risk of renal impairment and hyperkalemia.
• Co‑administration with potassium‑sparing diuretics or supplements: may cause dangerous hyperkalemia.
• Combined therapy with ACE inhibitors: heightened risk of renal dysfunction, hypotension and hyperkalemia.
• Non‑steroidal anti‑inflammatory drugs (NSAIDs): can reduce antihypertensive effect and impair renal function.

Moderate Interactions (Monitor Closely)

• Thiazide or loop diuretics: may enhance hypotensive response, requiring dose adjustment.
• Lithium: telmisartan can increase lithium levels, risking toxicity.
• Cyclosporine: may raise telmisartan plasma concentrations, necessitating monitoring.