Valsartan 80mg to Irbesartan Dose Equivalence
Valsartan 80mg is equivalent to irbesartan 150mg based on direct comparative clinical trials and guideline dosing recommendations.
Direct Evidence from Comparative Studies
The most robust evidence comes from head-to-head trials directly comparing these specific doses:
Valsartan 80mg demonstrates equivalent antihypertensive efficacy to irbesartan 150mg in hypertensive patients on chronic hemodialysis, with similar blood pressure reductions (150/79 mmHg vs 151/78 mmHg), comparable safety profiles, and similar rates of adverse events (15.4% vs 20.4% drug-related) 1
However, when combined with hydrochlorothiazide 12.5mg, irbesartan 150mg showed superior blood pressure lowering compared to valsartan 80mg (systolic BP reduction: -13.0 vs -10.6 mmHg, p=0.0094; diastolic BP reduction: -9.5 vs -7.4 mmHg, p=0.0007), with significantly higher normalization rates (50.2% vs 33.2%, p=0.0003) 2
Guideline-Based Dosing Context
The KDOQI guidelines establish standard dosing ranges that support this equivalence:
- Valsartan starting dose: 80-160mg daily, with goal dose of 80-320mg daily 3
- Irbesartan starting dose: 150mg daily, with goal dose of 150-300mg daily 3
These guideline recommendations position valsartan 80mg and irbesartan 150mg as comparable starting doses within their respective therapeutic ranges 3.
Clinical Implications for Conversion
When switching between these agents:
- Start irbesartan at 150mg when converting from valsartan 80mg, recognizing this represents a 1:1.875 dose ratio 2, 1
- The irbesartan dose may provide slightly greater blood pressure reduction, particularly at trough (morning measurements), so monitor for excessive BP lowering 2
- Both doses maintain comparable tolerability profiles with adverse event rates similar to placebo 1
Important Caveats
- For heart failure patients, do not routinely switch from valsartan to irbesartan unless there is a compelling reason, as valsartan has proven mortality benefit in heart failure trials at target doses of 160mg twice daily 4
- The equivalence holds best for hypertension management; irbesartan may demonstrate modestly superior efficacy when combined with diuretics 2, 5
- Valsartan 80mg represents a mid-range dose with established efficacy, while 160mg provides enhanced antihypertensive effect with maintained tolerability 6