When is Irbesartan (Angiotensin II receptor antagonist) indicated?

Indications for Irbesartan

Irbesartan is indicated for two primary conditions: hypertension (to lower blood pressure and reduce cardiovascular risk) and diabetic nephropathy in patients with type 2 diabetes, hypertension, elevated serum creatinine, and proteinuria >300 mg/day. 1

Primary Indication: Hypertension

Irbesartan is FDA-approved for treating hypertension to lower blood pressure, which reduces the risk of fatal and non-fatal cardiovascular events, primarily strokes and myocardial infarction. 1

Monotherapy vs. Combination Therapy

• Irbesartan may be used alone or in combination with other antihypertensive agents, particularly thiazide diuretics or calcium channel blockers. 1
• For most patients with confirmed hypertension (BP ≥140/90 mmHg), combination therapy is recommended as initial treatment, with preferred combinations being an ARB (like irbesartan) with either a dihydropyridine calcium channel blocker or thiazide diuretic. 2
• The combination of irbesartan with hydrochlorothiazide produces additive blood pressure-lowering effects. 3

Dosing for Hypertension

• Irbesartan provides 24-hour blood pressure control with once-daily dosing at 150-300 mg/day. 3, 4
• In clinical practice, irbesartan 150 mg can be titrated to 300 mg as needed for blood pressure control. 5

Secondary Indication: Diabetic Nephropathy

Irbesartan is specifically indicated for diabetic nephropathy in patients with type 2 diabetes who have all three of the following: hypertension, elevated serum creatinine, and proteinuria >300 mg/day. 1

Renoprotective Effects at Different Stages

For patients with type 2 diabetes, hypertension, and severely increased albuminuria (>300 mg/g), irbesartan 300 mg daily reduces the rate of nephropathy progression, including doubling of serum creatinine and end-stage renal disease. 2

• In the landmark IDNT trial, irbesartan 300 mg daily reduced the risk of doubling serum creatinine by 33% compared to placebo, independent of blood pressure reduction. 2, 3
• This renoprotective effect was superior to calcium channel blocker therapy (amlodipine) in head-to-head comparison. 2, 3

For patients with type 2 diabetes, hypertension, and moderately increased albuminuria (30-300 mg/g), irbesartan reduces progression to overt nephropathy. 2

• In the IRMA-2 trial, irbesartan 300 mg daily produced a nearly 3-fold reduction in progression to severely increased albuminuria compared to placebo, independent of blood pressure effects. 2, 3

Chronic Kidney Disease Without Diabetes

For patients with CKD without diabetes but with severely increased albuminuria (category A3), starting irbesartan or another ARB is recommended for those with high blood pressure. 2

• This recommendation is based on moderate-quality evidence showing cardiovascular and kidney benefits in this population. 2

For patients with CKD without diabetes and moderately increased albuminuria (category A2), irbesartan may be considered, though this is a weaker recommendation. 2

Important Clinical Considerations

Compelling Indications Beyond Blood Pressure

• Irbesartan reduces left ventricular hypertrophy in hypertensive patients with left ventricular hypertrophy. 3, 4
• The drug increases the probability of maintaining sinus rhythm after cardioversion of atrial fibrillation. 4

Critical Contraindications and Monitoring

Never combine irbesartan with ACE inhibitors or direct renin inhibitors, as dual RAS blockade increases risks of hyperkalemia and acute kidney injury without additional benefit. 2

• Monitor serum potassium and renal function when initiating irbesartan, especially in patients with chronic kidney disease. 6
• Hyperkalemia (>6 mEq/L) requiring discontinuation occurs rarely but must be monitored. 5
• Avoid in pregnancy. 2

Special Populations

In patients with chronic renal insufficiency, irbesartan 150-300 mg daily effectively lowers blood pressure while maintaining stable creatinine clearance and glomerular filtration rate. 5

• The blood pressure-lowering effect is accompanied by significant reduction in proteinuria in patients with chronic renal insufficiency. 5

In elderly patients (≥75 years), consider starting with a single agent rather than combination therapy, though the same blood pressure targets apply. 2