Losartan Every Other Day Dosing
No, losartan should not be taken every other day—it must be administered once daily (or twice daily in some cases) to maintain effective blood pressure control and organ protection. 1, 2
Why Daily Dosing is Required
The pharmacokinetic profile of losartan and its active metabolite E-3174 necessitates daily administration:
- Losartan reaches peak concentration 1-2 hours after administration, and its active metabolite E-3174 has a terminal half-life of only 6-9 hours 3
- This short half-life means drug levels fall below therapeutic thresholds well before 48 hours, leaving patients unprotected for extended periods with every-other-day dosing 3
- The FDA-approved dosing explicitly states losartan should be given "once daily" for all indications (hypertension, left ventricular hypertrophy, diabetic nephropathy) 1
Standard Dosing Regimens
For hypertension:
- Start at 50 mg once daily, with a maximum of 100 mg once daily 1
- The American College of Cardiology/American Heart Association guidelines allow for once or twice daily administration of the total daily dose, but never every other day 2
For heart failure with reduced ejection fraction:
- Target dose is 150 mg once daily based on the HEAAL trial, which demonstrated 10% relative risk reduction in death or heart failure hospitalization 2
- European Society of Cardiology recommends starting at 50 mg once daily and titrating to 150 mg once daily 4, 2
For diabetic nephropathy:
- Start at 50 mg once daily and increase to 100 mg once daily based on blood pressure response 1
Critical Dosing Considerations
Underdosing is a widespread problem in clinical practice:
- Less than 25% of patients are ever titrated to target doses, compromising cardiovascular and renal protection 2
- Higher doses provide greater benefits than lower doses, with little evidence that medium-range doses approximate the benefits of target doses 2
If tolerability is an issue:
- For patients with hepatic impairment, start at 25 mg once daily (still daily dosing) 1
- For patients with intravascular depletion or low blood pressure, start at the lowest dose and up-titrate slowly with small increments every 1-2 weeks, but maintain daily administration 2
- Consider adding a thiazide diuretic for additive blood pressure-lowering effects rather than reducing dosing frequency 2
Monitoring Requirements
- Check renal function and serum potassium within 1-2 weeks after starting treatment and after each dose increase 2
- Titrate no more frequently than every 2 weeks to target or maximally tolerated doses 2
The bottom line: Every-other-day dosing of losartan is not supported by pharmacokinetic data, FDA labeling, or clinical guidelines, and would result in inadequate blood pressure control and loss of cardiovascular and renal protection. 1, 3, 2