Irbesartan Viatris (Irbesartan)

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

• Hypertension: lowers elevated blood pressure and reduces cardiovascular risk.
• Diabetic nephropathy: slows decline of renal function in adults with type 2 diabetes.
• Proteinuria associated with diabetic kidney disease: reduces urinary protein excretion, helping preserve kidney health.

• Irbesartan selectively blocks angiotensin II type 1 (AT1) receptors on vascular smooth muscle, adrenal gland, and renal tubular cells. By preventing angiotensin II binding, it inhibits vasoconstriction, aldosterone secretion, and sympathetic activation, leading to reduced peripheral resistance, lower blood pressure, and decreased renal pressure that helps protect kidney function.

Common Side Effects

• Dizziness: feeling light‑headed, especially after standing.
• Headache: mild to moderate pain in the head region.
• Fatigue: general tiredness or lack of energy.
• Nausea: upset stomach or urge to vomit.
• Abdominal pain: discomfort in the stomach area.

Serious or Rare Side Effects

• Angioedema: swelling of the face, lips, tongue, or throat that may impair breathing.
• Severe hypotension: markedly low blood pressure causing faintness or shock.
• Hyperkalemia: elevated potassium levels that can affect heart rhythm.
• Acute renal impairment: sudden worsening of kidney function.
• Hepatic injury: abnormal liver enzyme elevations or liver dysfunction.

Before starting Irbesartan, consider the following precautions:

• Monitor blood pressure: ensure adequate control and avoid excessive lowering.
• Assess renal function: check serum creatinine and eGFR prior to initiation and periodically thereafter.
• Check serum potassium: hyperkalemia risk is higher in patients with renal impairment or those taking potassium‑sparing agents.
• Use caution in hepatic impairment: dose adjustments may be required.
• Avoid concurrent use with aliskiren in diabetic patients: increased risk of renal events.
• Store at room temperature: keep in the original packaging, protect from moisture and direct sunlight.

Irbesartan may interact with several medicines. Review the following groups:

Major Interactions (Avoid)

• Aliskiren in patients with diabetes: combined use can worsen renal function.
• Dual therapy with ACE inhibitors or other ARBs: increased risk of hyperkalemia and renal impairment.
• Potassium‑sparing diuretics (e.g., spironolactone): may cause dangerous potassium elevation.
• NSAIDs (e.g., ibuprofen, naproxen): can reduce antihypertensive effect and impair kidney function.
• Lithium: may raise lithium concentrations, leading to toxicity.

Moderate Interactions (Monitor Closely)

• ACE inhibitors: monitor potassium and renal function when used together.
• Thiazide diuretics: may enhance antihypertensive effect, requiring dose adjustment.
• Cyclosporine: increased risk of nephrotoxicity.
• Rifampin: may reduce plasma levels of Irbesartan.
• Digoxin: monitor for signs of digoxin toxicity as renal clearance may be affected.