Losartan 100mg Twice Daily Dosing
Losartan 100mg should not be taken twice daily as the maximum FDA-approved dose is 100mg once daily for hypertension. 1
FDA-Approved Dosing Guidelines
The FDA-approved dosing for losartan is clear:
- Initial starting dose: 50mg once daily
- Maximum dose: 100mg once daily 1
- The FDA label specifically states that the maximum recommended daily dose is 100mg 1
While the FDA label mentions that twice-daily dosing was studied in clinical trials, it concluded that once-daily dosing at the same total dose is sufficient for blood pressure control. The trough-to-peak ratio for systolic and diastolic responses was 50-95% and 60-90% respectively, indicating adequate 24-hour coverage with once-daily dosing. 1
Evidence Against Twice-Daily Dosing
A 2020 study directly compared once-daily versus twice-daily dosing of losartan and found no differences in blood pressure control between the two regimens. The study showed absolute differences in mean systolic BP ranging from -1.8 to 0.7 mmHg and diastolic BP ranging from -1.1 to 0.1 mmHg, with all confidence intervals crossing zero. 2
Special Considerations
In certain clinical scenarios, specific dosing recommendations apply:
- For hypertensive patients with left ventricular hypertrophy: Start with 50mg once daily, with potential increase to 100mg once daily 1
- For nephropathy in Type 2 diabetic patients: Start with 50mg once daily, with potential increase to 100mg once daily 1
- For patients with heart failure: While higher doses (up to 150mg daily) have been studied, the American College of Cardiology still recommends a maximum of 100mg daily 3
Pharmacokinetic Considerations
Losartan has a relatively short half-life (2 hours), but its active metabolite E3174 has a longer half-life (6-9 hours) and is 10-40 times more potent than losartan itself. This active metabolite provides sustained 24-hour blood pressure control with once-daily dosing. 4
Common Pitfalls to Avoid
Exceeding maximum recommended dose: Going beyond 100mg total daily dose is not supported by FDA labeling and may increase the risk of adverse effects without providing additional benefit.
Unnecessary twice-daily dosing: Research shows that once-daily dosing provides similar blood pressure control to twice-daily dosing at the same total dose. 2
Confusion with other medications: Some physicians may confuse losartan dosing with other ARBs that have different dosing schedules. For example, valsartan can be dosed up to 320mg daily (including BID dosing in some cases). 5, 3
In conclusion, while losartan has been studied in twice-daily regimens, the evidence and FDA approval support a maximum dose of 100mg once daily. If better blood pressure control is needed, adding a thiazide diuretic would be more appropriate than increasing to twice-daily dosing of losartan.