Olmesartan to Valsartan Conversion
When converting from olmesartan to valsartan, use a 1:8 ratio: olmesartan 20 mg daily converts to valsartan 160 mg daily, and olmesartan 40 mg daily converts to valsartan 320 mg daily. 1
Specific Conversion Ratios
- Olmesartan 20 mg once daily → Valsartan 160 mg daily (80 mg twice daily or 160 mg once daily) 1
- Olmesartan 40 mg once daily → Valsartan 320 mg daily (160 mg twice daily preferred for heart failure) 2, 1
- Olmesartan 10 mg once daily → Valsartan 80 mg daily 1
Dosing Schedule Considerations
For hypertension management, valsartan can be dosed once daily at the total daily dose, but for heart failure with reduced ejection fraction, valsartan should be dosed twice daily (e.g., 160 mg BID for the target dose of 320 mg daily). 2
The twice-daily dosing of valsartan in heart failure is critical because this was the regimen used in the landmark trials that demonstrated mortality benefit, with a target dose of 160 mg twice daily. 2
Clinical Context: When NOT to Convert
Avoid switching from valsartan to olmesartan in heart failure patients, as valsartan has proven mortality benefit in heart failure trials while olmesartan does not have equivalent evidence. 1 However, the reverse conversion (olmesartan to valsartan) is reasonable when guideline-directed medical therapy for heart failure is needed. 2
Post-Conversion Monitoring
Monitor blood pressure, serum creatinine, and potassium levels within 1-2 weeks after conversion. 1 This is essential because individual responses to ARBs can vary despite population-level dose equivalence, and both medications carry risks of hyperkalemia and acute kidney injury. 1, 3
Evidence Supporting Conversion Ratios
The conversion ratios are derived from comparative efficacy data showing that olmesartan 20 mg produces similar blood pressure reductions to valsartan 160 mg, and olmesartan 40 mg is equivalent to valsartan 320 mg. 4, 5 Multiple head-to-head trials demonstrated that olmesartan at lower milligram doses achieves comparable or superior blood pressure control compared to higher milligram doses of valsartan. 6, 4, 7, 5
Titration Strategy
Start valsartan at the equivalent dose based on the conversion ratio above, then titrate based on blood pressure response over 1-2 weeks rather than starting at a lower dose and working up. 1 This approach maintains therapeutic continuity and avoids a period of suboptimal blood pressure control during the transition.