Irbesartan Ciclum (Irbesartan)

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

• Hypertension: lowers systolic and diastolic blood pressure, reducing cardiovascular risk.
• Diabetic nephropathy: delays progression of renal disease in patients with type 2 diabetes.
• Proteinuria associated with diabetic kidney disease: reduces urinary protein excretion, helping preserve kidney function.

• Irbesartan selectively blocks angiotensin II type 1 (AT1) receptors on vascular smooth muscle and adrenal cells. By preventing angiotensin II binding, it inhibits vasoconstriction and aldosterone release, leading to vasodilation, reduced sodium and water retention, and ultimately lower blood pressure and decreased renal stress.

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.
• Nausea: upset stomach or urge to vomit.
• Diarrhea: loose, watery stools.
• Elevated blood potassium: mild hyperkalaemia detected in lab tests.

Serious or Rare Side Effects

• Angioedema: swelling of face, lips, tongue or throat that may impair breathing.
• Severe hypotension: marked drop in blood pressure causing faintness.
• Acute kidney injury: sudden decline in renal function.
• Liver enzyme elevation: increased ALT or AST levels.
• Myocardial infarction: rare occurrence of heart attack.
• Anaphylactic reaction: severe allergic response requiring immediate medical attention.

Before initiating therapy, clinicians should consider several safety measures.

• 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 concomitant potassium‑sparing agents.
• Use caution in hepatic impairment: dose adjustments may be needed.
• Avoid in pregnancy: potential fetal toxicity; discontinue if pregnancy is confirmed.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Irbesartan may interact with several medicines, requiring attention to avoid adverse outcomes.

Major Interactions (Avoid)

• Aliskiren (in diabetes): combined use can increase risk of renal impairment and hyperkalaemia.
• Dual ARB/ACE inhibitor therapy: may cause excessive hypotension and kidney injury.
• Potassium‑sparing diuretics (e.g., spironolactone): heightens risk of hyperkalaemia.
• High‑dose NSAIDs: can reduce renal perfusion and worsen kidney function.

Moderate Interactions (Monitor Closely)

• Lithium: may increase lithium serum levels, risking toxicity.
• Cyclosporine: can raise serum creatinine and potassium.
• Rifampin: may reduce irbesartan plasma concentrations.
• Thiazide diuretics: may enhance antihypertensive effect, requiring blood pressure monitoring.