Irbesartan Zentiva (Irbesartan)

Irbesartan is an angiotensin II receptor blocker used to treat conditions related to the renin‑angiotensin system.

• Hypertension: lowers blood pressure by reducing vascular resistance.
• Diabetic nephropathy: slows the progression of kidney damage in patients with type 2 diabetes.
• Proteinuria associated with diabetic kidney disease: reduces urinary protein excretion.

• Irbesartan selectively antagonizes angiotensin II type 1 (AT1) receptors on vascular smooth muscle, adrenal gland, and renal tubular cells. Blocking these receptors prevents angiotensin II‑mediated vasoconstriction, aldosterone secretion, and sodium‑water retention, resulting in decreased systemic vascular resistance and lowered blood pressure, while also mitigating renal and cardiac remodeling.

Common Side Effects

• Dizziness: feeling light‑headed, especially after standing.
• Headache: mild to moderate pain in the head region.
• Fatigue: unusual tiredness or lack of energy.
• Nausea: feeling of stomach upset or urge to vomit.
• Hyperkalaemia: elevated potassium levels in blood tests.
• Cough: occasional dry throat irritation.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips, tongue, or throat that may impair breathing.
• Acute renal impairment: sudden decline in kidney function.
• Severe hypotension: markedly low blood pressure causing faintness.
• Hepatic injury: abnormal liver enzyme elevations.
• Neutropenia: low neutrophil count increasing infection risk.
• Anaphylactic reaction: severe allergic response requiring immediate medical attention.

Before initiating therapy, patients should be evaluated for renal function, electrolyte balance, and blood pressure stability.

• Monitor blood pressure: ensure target levels are achieved without excessive drop.
• Assess renal function: check serum creatinine and eGFR periodically.
• Check serum potassium: avoid hyperkalaemia, especially with potassium‑sparing agents.
• Use caution in hepatic impairment: dose adjustment may be required.
• Avoid use in pregnancy unless clearly needed: potential fetal risk.
• Store at room temperature: keep in the original pack, protect from moisture and direct sunlight.

Irbesartan may interact with several medicines that affect renal function, potassium balance, or drug metabolism.

Major Interactions (Avoid)

• Aliskiren (in patients with diabetes): combined use can increase renal risk.
• Concurrent ACE inhibitor or ARB therapy: may cause excessive potassium rise and kidney injury.
• Potassium‑sparing diuretics (e.g., spironolactone): heightens risk of hyperkalaemia.

Moderate Interactions (Monitor Closely)

• Lithium: irbesartan can raise lithium levels, requiring serum monitoring.
• NSAIDs (e.g., ibuprofen): may reduce antihypertensive effect and impair renal function.
• Rifampin: may lower irbesartan plasma concentrations, reducing efficacy.