Medically reviewed by Jessica Swirble, PharmD
Last updated on March 27, 2025
Drug Information | Side Effects | Use & Dosage | Request an Online Prescription
Losartan is an ARB medication used alone or in conjunction with other medications to treat high blood pressure. It is also used to reduce the risk of stroke in patients who have high blood pressure or heart conditions. Losartan is also used to treat kidney damage due to diabetes (diabetic nephropathy).
Losartan is prescribed to treat high blood pressure (hypertension). It is also used to help protect the kidneys from damage due to diabetes. It is also used to lower the risk of stroke in patients with hypertension and left ventricular hypertrophy.
Losartan belongs to a class of medications known as angiotensin II receptor blockers (ARBs). These drugs work by blocking the action of angiotensin II, a substance in the body that causes blood vessels to narrow, thereby reducing blood pressure and improving blood flow.
Losartan is available as an oral tablet to be taken by mouth.
It can take 3 to 6 weeks before losartan takes effect and begins to lower blood pressure.
High blood pressure does not always cause noticeable symptoms. Therefore, you might not feel the effects of losartan. That doesn’t mean that the medication is not working.
Take losartan for as long as your provider tells you to.
Losartan may be prescribed to treat heart failure in some patients; talk to your healthcare provider about other uses for this medication, if appropriate.
Losartan is available as an oral tablet that should be taken by mouth.
Losartan is available in its generic form (as “losartan” or “losartan potassium”) or under the brand name Cozaar.
Losartan is only available via prescription. You must have a written prescription from a licensed healthcare provider to obtain this medication.
The use of losartan has been shown to cause side effects in some patients.
Common mild side effects of losartan use include:
More severe side effects include:
Seek medical attention immediately if you experience any severe symptoms while taking losartan. If you experience mild side effects that become severe or do not go away after a few days, speak to a healthcare provider right away.
Tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with losartan. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with this drug.
Tell your provider if you are taking these medications or supplements:
You should also mention medical conditions such as:
If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before using losartan to assess potential risks and benefits.
You should avoid taking salt substitutes containing potassium while taking losartan. Talk to your healthcare provider about the use of this drug with food, beverages, alcohol, and tobacco. Your provider may recommend that you follow a low-sodium diet while taking losartan.
Your healthcare provider will tell you if you should avoid certain foods, beverages, or products while using losartan. It is extremely important to follow their guidance, as certain drugs can interact with other substances in the body---leading to potentially severe reactions. If you have any questions about special instructions you should follow while taking this drug, talk to your healthcare provider before use.
Losartan is usually prescribed along with healthy lifestyle changes like a reduced-calorie diet and increased physical activity to control blood pressure. Follow your healthcare provider’s guidance regarding these habits while taking losartan.
The symptoms of a losartan overdose include:
If you experience any of these symptoms, call the poison control helpline at 1-800-222-1222. If an individual has collapsed, is having seizures, or is unresponsive, call 9-1-1 immediately.
Losartan is available in the following forms:
The typical starting dose of losartan varies depending on the condition being treated, the severity of the condition, and individual patient factors. It is important to follow your healthcare provider's instructions regarding dosage and administration.
For hypertension (high blood pressure), the typical starting doses may be:
For patients with liver impairment or those taking diuretics, the starting dose may be lower.
Your healthcare provider will determine the most appropriate dose based on your medical history, current medications, and response to the medication.
Losartan should be taken exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment without consulting your provider.
If you have any questions about your dosage, contact your healthcare provider. If you want to talk to a provider right away, book an online doctor appointment on Sesame to discuss your concerns.
If you miss a dose, take it as soon as you remember it. If it's almost time for another dose of losartan, skip the missed dose and take your next dose as scheduled. Do not take or apply a double dose of losartan.
Do not discontinue or alter your losartan dosage without consulting with your healthcare provider. Follow your healthcare provider's instructions regarding dosing and other recommendations for taking losartan.
Store losartan as directed by your healthcare provider or pharmacist. Proper storage is essential to maintain the medication's effectiveness. losartan should be stored at room temperature, away from excessive heat, light, and moisture.
Keep the medication out of the reach of children and ensure that the container is tightly closed.