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 blood pressure control; for diabetic nephropathy, use 300 mg once daily as the standard dose. 1
Standard Dosing by Indication
Hypertension
- Initial dose: 150 mg once daily 2, 1
- Maximum dose: 300 mg once daily 2, 1
- May be administered with or without food 1
- Provides 24-hour blood pressure control with once-daily dosing 3, 4
Diabetic Nephropathy (Type 2 Diabetes)
- Recommended dose: 300 mg once daily 2, 1
- This dose provides renoprotective effects independent of blood pressure lowering 5, 6
- In the landmark IDNT trial, irbesartan 300 mg daily reduced the risk of doubling serum creatinine by 33% compared to placebo and 37% compared to amlodipine 6
- For early nephropathy (microalbuminuria), irbesartan 300 mg daily demonstrated a 70% risk reduction in progression to overt proteinuria 6
Special Populations Requiring Dose Adjustment
Volume- or Salt-Depleted Patients
- Initial dose: 75 mg once daily 1
- This applies to patients treated vigorously with diuretics or on hemodialysis 1
- After volume repletion, titrate to standard doses 1
Renal Impairment
- No dose adjustment required for chronic kidney disease 3, 7
- Irbesartan is excreted by both biliary and renal routes, eliminating the need for dosage adjustments in renal disease 3
- In patients with moderate-to-severe renal insufficiency, irbesartan 150-300 mg daily effectively reduced blood pressure without adversely affecting creatinine clearance or glomerular filtration rate 7
Hepatic Impairment
- No dose adjustment required 3
Dosing Algorithm Based on KDOQI Guidelines
The KDOQI guidelines provide a structured approach to ARB dosing in diabetic kidney disease 2:
Starting dose: 150 mg daily 2
Goal dose: 150-300 mg daily 2
Target: Aim for the higher end of the dose range (300 mg) when possible 2
Combination Therapy Considerations
- Irbesartan may be combined with thiazide diuretics for additive blood pressure reduction 2, 3
- Never combine with ACE inhibitors or direct renin inhibitors due to increased risks of hypotension, hyperkalemia, and acute renal failure without additional cardiovascular benefit 8, 9
- Avoid potassium-sparing diuretics or potassium supplements, especially in patients with CKD or diabetes, due to compounded hyperkalemia risk 8
Monitoring Requirements
Initial Monitoring
- Check serum creatinine and potassium within 2-4 weeks after initiation or dose increase 8
- A modest rise in serum creatinine (10-20%) is expected and hemodynamic, not indicative of kidney injury unless persistent 8
Action Thresholds
- If creatinine rises >30% within 4 weeks: Consider discontinuing unless rise is transient 8
- If potassium rises to >5.5 mmol/L: Halve the dose 8
- If potassium rises to ≥6.0 mmol/L: Stop irbesartan immediately 8
Common Pitfalls to Avoid
- Underdosing in diabetic nephropathy: The renoprotective benefit is dose-dependent; 300 mg daily showed significantly greater benefit than 150 mg daily (70% vs 39% risk reduction in progression) 6
- Failing to temporarily hold during intercurrent illness: Counsel patients to hold irbesartan during volume depletion, bowel preparation for colonoscopy, or prior to major surgery to prevent acute kidney injury 8
- Combining with other RAS inhibitors: This increases adverse effects without additional benefit and is contraindicated 8, 9
- Inadequate monitoring in high-risk patients: Those with renal artery stenosis, severe heart failure, or advanced CKD require closer monitoring for acute renal failure 8