Micardis (Telmisartan)

Micardis (telmisartan) is an angiotensin II receptor blocker used to manage conditions related to the renin‑angiotensin system.

• Hypertension: reduces systolic and diastolic blood pressure, helping patients achieve target levels.
• Cardiovascular risk reduction: lowers the incidence of myocardial infarction, stroke and cardiovascular death in high‑risk individuals.
• Diabetic nephropathy (off‑label in some regions): slows progression of renal impairment associated with type 2 diabetes.

• Telmisartan selectively blocks the angiotensin II type 1 (AT1) receptor, preventing angiotensin II‑mediated vasoconstriction, aldosterone release, and sympathetic activation. This inhibition leads to relaxation of vascular smooth muscle, reduced peripheral resistance, and decreased sodium and water retention, ultimately lowering blood pressure and providing cardiovascular protection.

Telmisartan may cause a range of adverse reactions, most of which are mild and reversible.

Common Side Effects

• Dizziness: sensation of light‑headedness, especially after standing.
• Headache: mild to moderate intensity, often transient.
• Fatigue: general feeling of tiredness without exertion.
• Back pain: discomfort in the lumbar region.
• Upper respiratory tract infection: symptoms such as sore throat or nasal congestion.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips, tongue or throat that may compromise breathing.
• Acute renal impairment: sudden decrease in kidney function, indicated by rising creatinine.
• Hepatic injury: elevated liver enzymes or jaundice.
• Severe hypotension: marked drop in blood pressure causing faintness or shock.
• Allergic reactions: rash, pruritus or anaphylaxis.

Before initiating therapy, clinicians should consider several safety measures.

• Renal function monitoring: assess serum creatinine and eGFR periodically.
• Electrolyte balance: check potassium levels, especially when combined with potassium‑sparing agents.
• Hepatic impairment: use with caution in patients with moderate to severe liver disease.
• Pregnancy: contraindicated in the second and third trimesters due to fetal toxicity.
• Elderly patients: start at lower doses and monitor for orthostatic hypotension.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Telmisartan can interact with several medicines, requiring attention to avoid reduced efficacy or increased toxicity.

Major Interactions (Avoid)

• Aliskiren in diabetic patients: combined use may increase risk of renal dysfunction.
• Potassium‑sparing diuretics or supplements: may cause dangerous hyperkalemia.
• ACE inhibitors: concurrent use can lead to additive renal impairment.
• NSAIDs: may blunt antihypertensive effect and affect renal function.
• Lithium: telmisartan can raise lithium concentrations, risking toxicity.

Moderate Interactions (Monitor Closely)

• Thiazide diuretics: may enhance hypotensive response.
• CYP2C9 inhibitors (e.g., fluconazole): can increase telmisartan plasma levels.
• CYP3A4 inducers (e.g., rifampin): may reduce drug exposure.
• Antidiabetic agents: blood glucose may improve, requiring dose adjustment.
• Warfarin: occasional changes in INR have been reported; monitor coagulation status.