The highest FDA-approved dose of losartan is 100 mg per day for adults treating high blood pressure or diabetic kidney disease. In clinical trials for heart failure, doses up to 150 mg daily have been studied and shown added benefit, though this exceeds the standard labeled maximum.
Standard Maximum for Blood Pressure
For high blood pressure, losartan is typically started at 50 mg once daily and can be increased to 100 mg once daily. That 100 mg ceiling exists because research shows the blood pressure lowering effect essentially plateaus beyond 50 mg. In a randomized trial published in the American Heart Association’s journal Hypertension, doses above 50 mg provided no additional average reduction in blood pressure at peak effect (six hours after dosing). The 50 to 100 mg range delivered the maximum reduction in blood pressure over a full 24-hour period, dropping diastolic pressure by roughly 10 points from baseline.
So why does the 100 mg option exist if 50 mg captures most of the benefit? The answer is timing. At the end of the dosing interval (right before your next pill), the higher dose helps maintain steadier blood pressure control throughout the day. For some people, 50 mg wears off before the next dose, and going to 100 mg fills that gap. If 100 mg still isn’t enough, the usual next step is adding a second blood pressure medication rather than increasing losartan further.
The 150 mg Dose in Heart Failure
A large international trial called HEAAL compared 150 mg of losartan daily against 50 mg in 3,834 patients with heart failure and reduced heart function. The study followed patients for an average of 4.7 years, and the results were clear: the higher dose reduced deaths from all causes and hospitalizations for heart failure more effectively than the lower dose.
The tradeoff was a modest increase in side effects. Patients on 150 mg experienced higher rates of low blood pressure, kidney function changes, and elevated potassium levels compared to those on 50 mg. Potassium levels rose by a small amount (0.1 mmol/L on average), and the absolute difference in high potassium events was only 2 to 3 percent between groups. Critically, very few patients (less than 1 percent) had to stop taking the medication because of these issues. Researchers concluded that the benefit of the higher dose outweighed the risks.
This 150 mg dose is not a standard prescription for blood pressure management. It has been used specifically in the context of heart failure, where the goals of treatment differ from simple blood pressure control.
Doses for Children
In children ages 6 and older, losartan dosing is based on body weight. The maximum studied pediatric dose is 1.4 mg per kilogram of body weight per day, with an absolute cap of 100 mg daily. Doses above that threshold have not been studied in children, so there is no safety data to support going higher.
Lower Starting Doses for Certain Groups
Not everyone starts at the standard 50 mg dose, and for some people, even the usual maximum may not be appropriate. If you have mild to moderate liver impairment, the recommended starting dose drops to 25 mg once daily. Losartan is converted into its active form by the liver, so reduced liver function means the drug behaves differently in your body. It has not been studied at all in people with severe liver disease.
Kidney impairment on its own doesn’t require a dose change. However, if you’re volume depleted (common if you’re also taking a diuretic or water pill), the starting dose is reduced to 25 mg to avoid a sharp drop in blood pressure. Your body is more sensitive to blood pressure medications when fluid levels are low.
What Happens if You Take Too Much
Taking more losartan than prescribed primarily causes blood pressure to drop too low. Symptoms can include dizziness, lightheadedness, and sometimes a rapid heartbeat as the body tries to compensate. In one documented case, a young child who accidentally swallowed 200 mg (eight 25 mg tablets) experienced vomiting, a skin rash, dizziness, and low blood pressure readings over several hours of hospital observation.
Losartan overdoses are generally not life-threatening in otherwise healthy people, but sustained low blood pressure can become dangerous, particularly for anyone with existing heart or kidney problems. If you accidentally take an extra dose and feel fine, it’s still worth contacting Poison Control (1-800-222-1222) for guidance on whether monitoring is needed.