Irbesartan Viatris (Irbesartan)

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

• Hypertension: lowers elevated blood pressure and reduces cardiovascular strain.
• Diabetic nephropathy: slows progression of kidney damage in patients with type 2 diabetes.
• Heart failure: used as part of combination therapy to improve cardiac output and reduce fluid overload.

• Irbesartan selectively blocks angiotensin II type 1 (AT1) receptors on vascular smooth muscle and adrenal tissue, preventing angiotensin II‑mediated vasoconstriction and aldosterone release. This inhibition leads to vasodilation, reduced sodium and water retention, and ultimately lower systemic blood pressure and decreased renal workload.

Irbesartan may cause a range of adverse reactions, from mild to severe.

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: upset stomach or urge to vomit.
• Hyperkalaemia: elevated potassium levels detectable in blood tests.

Serious or Rare Side Effects

• Angioedema: swelling of the face, lips, tongue or throat that may impair breathing.
• Acute renal impairment: sudden decline in kidney function, indicated by rising creatinine.
• Hepatic injury: signs of liver damage such as jaundice or elevated enzymes.
• Severe hypotension: dangerously low blood pressure causing faintness or shock.
• Allergic reactions: rash, itching, or hives that may progress to systemic involvement.

Before initiating therapy, clinicians should consider several safety measures.

• Blood pressure monitoring: check regularly to avoid excessive lowering.
• Renal function assessment: evaluate serum creatinine and eGFR at baseline and during treatment.
• Serum potassium surveillance: monitor especially when combined with potassium‑sparing agents.
• Hepatic impairment caution: adjust use in patients with liver disease.
• Pregnancy avoidance: discontinue if pregnancy is confirmed or planned.
• Store at ambient temperature: keep below 25 °C in the original container, protect from moisture and direct sunlight.

Irbesartan can interact with several drug classes, requiring attention to avoid adverse outcomes.

Major Interactions (Avoid)

• Aliskiren: concurrent use may increase risk of renal dysfunction and hyperkalaemia.
• ACE inhibitors: combined therapy raises the chance of angioedema and severe hypotension.
• Potassium‑sparing diuretics or supplements: may cause dangerous hyperkalaemia.

Moderate Interactions (Monitor Closely)

• NSAIDs: can blunt antihypertensive effect and affect renal perfusion.
• Lithium: may raise lithium concentrations, risking toxicity.
• Loop or thiazide diuretics: can enhance the blood‑pressure‑lowering effect, requiring dose adjustments.