From the Guidelines
Losartan can start to lower blood pressure within a few hours of taking the first dose, but it may take several days to a few weeks to see the full effect. The medication works by blocking the angiotensin II receptors, which allows the blood vessels to relax and widen, thereby reducing blood pressure [ 1 ].
Key Points to Consider
- Losartan is usually started at 50 mg once daily, though some patients may begin with 25 mg, with doses potentially increasing to a maximum of 100 mg daily based on blood pressure response.
- It's essential to take losartan consistently at the same time each day, even if you feel well, as stopping suddenly can cause your blood pressure to increase rapidly.
- During the initial weeks of treatment, your doctor may recommend more frequent blood pressure monitoring to assess how well the medication is working for you and make any necessary dosage adjustments.
Evidence-Based Recommendations
The Losartan Intervention for Endpoint Reduction (LIFE) study [ 1 ] demonstrated the effectiveness of losartan in reducing cardiovascular morbidity and mortality in patients with hypertension and left ventricular hypertrophy.
Important Considerations
- The study found that losartan had a lower risk for cardiovascular end points and all-cause mortality compared to atenolol in a prespecified diabetes subgroup [ 1 ].
- The evidence suggests that losartan can be an effective treatment option for patients with hypertension, particularly those with diabetes or left ventricular hypertrophy.
From the FDA Drug Label
The effect of losartan is substantially present within one week but in some studies the maximal effect occurred in 3 to 6 weeks. The time to onset of action of losartan for blood pressure control is within one week, but the maximal effect may take 3 to 6 weeks to occur.
- The antihypertensive effect of losartan is dose-dependent and can be observed at trough levels after administration.
- Peak effects are uniformly larger than trough effects, with a trough-to-peak ratio of 50 to 95% for systolic responses and 60 to 90% for diastolic responses. 2
From the Research
Blood Pressure Control with Losartan
- The time it takes for losartan to begin controlling blood pressure is not explicitly stated in the provided studies, but its effectiveness in lowering blood pressure has been demonstrated in several trials 3, 4, 5, 6.
- A study from 1995 found that losartan potassium significantly decreased mean systolic and diastolic 24-hour ambulatory blood pressure compared to placebo, with all doses showing a smooth, sustained antihypertensive effect 3.
- Another study from 2007 compared the effectiveness of losartan/hydrochlorothiazide combination therapy to candesartan/amlodipine combination therapy and found that both combinations significantly reduced blood pressure, with similar efficacy 4.
- The ALPHABET study from 2012 found that losartan/hydrochlorothiazide combination therapy and high-dose amlodipine monotherapy had similar effects on blood pressure control, but losartan/hydrochlorothiazide had a superior effect on reducing urinary albumin/creatinine ratio 5.
- A 2019 study found that different combinations of antihypertensive therapy, including losartan with or without hydrochlorothiazide, were equally effective in reducing blood pressure and improving arterial stiffness in patients with essential hypertension 6.
Onset of Action
- While the exact onset of action for losartan is not specified in the provided studies, the 1995 study found that losartan potassium had a significant blood pressure-lowering effect after 24 hours of treatment, suggesting that it can begin to take effect within a day or two of initiation 3.
- However, it is likely that the full effects of losartan on blood pressure control may take several days to several weeks to become apparent, as blood pressure can fluctuate and may take time to stabilize in response to treatment.