What is the recommended dosage and usage of Irbesartan (Angiotensin II Receptor Blocker) for patients with hypertension or diabetic nephropathy?

Irbesartan Dosing for Hypertension and Diabetic Nephropathy

For hypertension, start irbesartan at 150 mg once daily and titrate to 300 mg once daily as needed; for diabetic nephropathy, use 300 mg once daily as this dose provides optimal renoprotective effects. 1, 2

Dosage Recommendations by Indication

Hypertension

• Initial dose: 150 mg once daily 1
• Maximum dose: 300 mg once daily as needed for blood pressure control 1
• Special populations: 75 mg once daily for volume or salt-depleted patients (e.g., those on intensive diuretic therapy or hemodialysis) 1

Diabetic Nephropathy

• Recommended dose: 300 mg once daily 1
• This dose has been shown to reduce the risk of progression to overt nephropathy by approximately 70% in patients with type 2 diabetes and microalbuminuria 2
• The 300 mg daily dose reduced the risk of doubling serum creatinine by 33% and end-stage kidney disease by 23% in patients with type 2 diabetes and overt nephropathy 2, 3

Administration Guidelines

• May be administered with or without food 1
• Can be given with other antihypertensive agents 1
• Once-daily dosing provides effective 24-hour blood pressure control 4

Monitoring Recommendations

• Check serum creatinine, potassium, and blood pressure within 2-4 weeks of starting or increasing the dose 2
• Ongoing monitoring of kidney function and potassium levels at least annually 2
• For patients with diabetic nephropathy, monitor urinary albumin excretion to assess treatment response 3

Combination Therapy

• If blood pressure targets are not achieved with irbesartan monotherapy, consider adding:
  • Dihydropyridine calcium channel blocker
  • Thiazide-like diuretic 2
• Use caution with potassium-sparing diuretics, potassium supplements, or other medications that may increase potassium levels 2

Important Precautions

• Contraindicated in pregnancy 2
• Use with caution in patients with:
  • Volume depletion
  • Risk of hyperkalemia 2
  • Severe renal or hepatic impairment (though dosage adjustments are generally not required) 5

Clinical Pearls

• Irbesartan's renoprotective effects in diabetic nephropathy are partly independent of its blood pressure-lowering effects 4, 3
• The 300 mg dose has demonstrated superior renoprotection compared to amlodipine 10 mg in patients with diabetic nephropathy 3
• Irbesartan has shown efficacy in both early (microalbuminuria) and late (overt proteinuria) diabetic nephropathy 3
• The medication has a favorable tolerability profile with adverse event rates similar to placebo in clinical trials 4, 6