Does it matter if losartan (angiotensin II receptor antagonist) is taken in the morning or at night?

Timing of Losartan Administration

It does not matter whether losartan is taken in the morning or at night—what matters most is taking it at the same time each day to establish a consistent routine that improves medication adherence. 1

Evidence-Based Recommendation

The most recent and highest-quality guideline evidence directly addresses this question:

• The 2024 ESC Guidelines for the Management of Elevated Blood Pressure and Hypertension explicitly state that current evidence does not show benefit of diurnal timing of blood pressure-lowering drug administration on major cardiovascular outcomes. 1

• Patients should be encouraged to take medications at the most convenient time of day to improve adherence, and at the same time each day in a consistent setting. 1

Supporting Evidence from Other Guidelines

• The American Diabetes Association guidelines (2019,2021) note that while there is an association between absence of nocturnal blood pressure dipping and cardiovascular disease incidence, a meta-analysis found only a small benefit of evening versus morning dosing on blood pressure control with no data on clinical effects (morbidity/mortality outcomes). 1

• These guidelines acknowledge growing evidence about bedtime dosing but do not make definitive recommendations favoring one timing over another. 1

Pharmacokinetic Considerations

From a pharmacological standpoint, losartan's properties support flexible timing:

• Losartan reaches maximum concentrations 1-2 hours after administration and is converted to its active metabolite E-3174, which has an estimated terminal half-life of 6-9 hours. 2

• The pharmacokinetics are linear and dose-proportional, and losartan can be administered without regard to food. 2

• The maximum recommended daily dose is 100mg, which can be given as a once-daily dose. 2

Important Caveats

Dosing Frequency vs. Timing

Do not confuse timing (morning vs. evening) with frequency (once-daily vs. twice-daily):

• One small study suggested twice-daily administration (morning and evening) of the same total daily dose may be more effective at eliminating non-dipper phenomenon compared to once-daily evening dosing. 3

• However, a larger real-world study found no differences in blood pressure control or safety between twice-daily and once-daily dosing regimens. 4

• The key issue is achieving adequate total daily dosing—studies show 150mg daily is superior to 50mg daily for heart failure outcomes. 1, 5

Practical Application

The priority should be:

1. Ensuring adequate total daily dose (typically 50-100mg for hypertension, up to 150mg for heart failure if tolerated) 1
2. Establishing a consistent daily routine at whatever time maximizes adherence 1
3. Taking at the same time each day 1

Bottom line: Choose morning or evening based on patient preference and what fits best into their daily routine—consistency and adherence matter far more than the specific time of day for cardiovascular outcomes. 1