Irbesartan Fair-Med (Irbesartan)

Irbesartan acts on the renin‑angiotensin‑aldosterone system to control blood pressure and renal disease progression.

• Hypertension: reduces systolic and diastolic pressure, helping achieve target blood pressure goals.
• Diabetic nephropathy: slows the decline of renal function in patients with type 2 diabetes.
• Proteinuria associated with diabetic kidney disease: decreases urinary protein excretion, supporting kidney preservation.

• Irbesartan selectively blocks the angiotensin II type 1 (AT1) receptor, preventing angiotensin II from inducing vasoconstriction and aldosterone release. This antagonism leads to relaxation of vascular smooth muscle, reduced peripheral resistance, and decreased sodium and water retention, thereby lowering blood pressure and mitigating renal damage.

Irbesartan is generally well tolerated, but adverse reactions can occur.

Common Side Effects

• Dizziness: feeling light‑headed, especially after standing quickly.
• Headache: mild to moderate intensity.
• Fatigue: unusual tiredness without exertion.
• Nausea: upset stomach or feeling of needing to vomit.
• Elevated potassium: mild hyperkalaemia detected on blood tests.

Serious or Rare Side Effects

• Angioedema: swelling of the face, lips, tongue or throat requiring immediate medical attention.
• Acute renal failure: sudden loss of kidney function, indicated by reduced urine output or rising creatinine.
• Severe hypotension: dangerous drop in blood pressure causing faintness or shock.
• Hepatic injury: abnormal liver enzymes or jaundice.
• Neutropenia: marked decrease in white blood cells, increasing infection risk.

Before initiating therapy, clinicians should evaluate patient‑specific factors and monitor key parameters.

• Blood pressure monitoring: check regularly to ensure therapeutic response and avoid excessive lowering.
• Renal function assessment: measure serum creatinine and eGFR before and during treatment.
• Serum potassium surveillance: monitor especially in patients with renal impairment or those taking potassium‑sparing agents.
• Hepatic impairment caution: adjust use in patients with moderate to severe liver disease.
• Hypersensitivity awareness: discontinue if signs of allergic reaction such as rash or angioedema appear.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Irbesartan may interact with other medicines, altering efficacy or safety.

Major Interactions (Avoid)

• Concomitant use with aliskiren in diabetic patients: increased risk of renal impairment, hyperkalaemia and hypotension.
• Dual blockade with ACE inhibitors or other ARBs: heightened chance of kidney dysfunction and low blood pressure.
• Potassium‑sparing diuretics (e.g., spironolactone): may cause dangerous hyperkalaemia.

Moderate Interactions (Monitor Closely)

• Non‑steroidal anti‑inflammatory drugs (NSAIDs): can reduce antihypertensive effect and impair renal function.
• Lithium: may raise lithium concentrations, risking toxicity.
• Strong CYP3A4 inhibitors (e.g., azole antifungals): can increase irbesartan plasma levels, requiring dose adjustment.