Losartan: Usage, Side Effects, Dosage, Precautions


Cozaar (losartan potassium, also known as losartan) is an oral medication widely used to treat high blood pressure (hypertension) and the complications of other conditions associated with high blood pressure. This is not a cure for a disease, but simply a way to cope with it.

Researchers are also investigating its possible use to treat complications of COVID-19 , although its effectiveness is not yet known. Cozaar (losartan) belongs to a class of medications known as angiotensin II receptor blockers (ARBs) . It is taken in tablet form.

As an angiotensin II receptor blocker, losartan helps your blood vessels relax to lower blood pressure and make it easier for your heart to pump blood through your body. It does this by blocking the action of the hormone angiotensin II , which otherwise narrows veins and arteries, raises blood pressure, and forces the body to retain more fluid and sodium .

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Losartan is approved by the FDA to lower blood pressure that is too high, which means you have a systolic pressure in the arteries (when the heart beats) of 130 mmHg. or diastolic pressure or higher (between beats) 80 mm Hg. up .

The drug is also approved by the FDA to reduce the risk of stroke in people with high blood pressure and left ventricular hypertrophy, a heart condition also known as an enlarged heart. However, this may not reduce the risk of stroke in black people with these conditions .

Additionally, losartan is approved by the FDA to treat kidney damage in people with type 2 diabetes , a condition that occurs when the body does not use insulin efficiently and blood glucose (sugar) levels are too high .

Use not indicated on the label

Patients with severe lung damage associated with COVID-19 have higher levels of angiotensin II in the body. This hormone constricts your blood vessels, increases your blood pressure, and forces your body to retain more fluid. Losartan helps block these actions of angiotensin II in people with hypertension .

This is one of the reasons researchers are studying losartan for the treatment of COVID-19 patients, although there is insufficient data to confirm its efficacy. These include inpatient clinical trials, scheduled for completion in April 2021 .

Before drinking

If you have any of the following conditions, you may be prescribed losartan alone or in combination with other medications:

  • High blood pressure
  • Type 2 diabetes and kidney damage
  • High blood pressure and an enlarged heart.

Talk to your doctor about all the medications, supplements, and vitamins that you are currently taking. While some medications pose a lower risk of interaction, others may directly contraindicate their use or cause careful consideration of whether the benefits of treatment outweigh the disadvantages in your case.

Precautions and contraindications.

People who are pregnant or planning to become pregnant should not take this drug as it can cause death or serious injury to the fetus during the last six months of pregnancy. This also applies when losartan is also taken in combination with the diuretic hydrochlorothiazide under the brand name Hyzaar.

You should tell your doctor if you have ever had kidney or liver disease, heart failure, as this information will help your doctor understand how and if to prescribe it. Also inform if you are allergic to losartan or have diabetes and also take aliskiren (brand name Tekturna and in Amturnide, Tekamlo, Tekturna HCT). In such circumstances, you will most likely be advised not to take losartan.

Tell your doctor if you are breastfeeding, as small amounts of the drug can pass into breast milk and lower your baby's blood pressure.

Not everyone responds equally to ARBs as losartan. A 2018 review of hypertension studies found that black patients were, on average, less sensitive to ARBs (when used alone) than white patients.

However, ARB treatment has been found to be just as effective in blacks when used in combination with one or both of the following blood pressure-lowering medications: thiazide diuretics , which cause fluid to drain from the body increasing the flow of urine; and calcium channel blockers , which relax narrowed blood vessels.

There is also evidence that losartan may not reduce the risk of stroke in black people with hypertension and an enlarged heart.

Other angiotensin receptor blockers

Other angiotensin receptor blockers (ARBs) have similar contraindications. These include :

  • Atacand (candesartan)
  • Avapro (irbesartan)
  • Benicar (olmesartan)
  • Diovan (valsartan)
  • Edarbi (azilsartan)
  • Mikardis (Telmisartan)
  • Teveten (eprosartan)


Losartan is usually taken by mouth in the following doses, depending on the condition being treated.


  • Adults: 50 milligrams (mg) a day.
  • Children: 0.7 mg per kilogram of body weight per day at 50 mg.

For hypertensive patients with an enlarged heart, the usual starting dose is 50 mg per day. For patients with type 2 diabetes mellitus with kidney disease, the usual dose is 50 mg per day.

All indicated doses are indicated by the manufacturer of the drug. Check your prescription and talk to your doctor to make sure you are taking the correct dose.

How to take and store

Losartan should be taken exactly as prescribed by your doctor. It can be taken with or without food. If you miss a dose, take it as soon as you remember; But if it is close to your next dose, skip the missed dose. Just take your next dose at the usual time.

If you take too much losartan, call your doctor, poison control center, or get emergency medical help.

Store losartan in a tightly closed container, protecting the medicine from light. It should be stored between 59 F and 86 F (15 C to 30 C). Keep out of the reach of children.

Side effects

Severe form

The most common side effects of taking losartan include the following :

  • Dizziness or dizziness
  • Headache
  • Nausea
  • Threw up
  • Diarrhea
  • Joint pain
  • Muscle pain


Rare but serious side effects can include:

  • Jaundice : the skin turns yellowish.
  • Inflammation of the pancreas: the symptom is severe abdominal pain.
  • Blood or bone marrow disorders: Signs may include fatigue, fever, paleness, or purple spots.
  • Changes in blood sodium and potassium levels: May cause muscle cramps or irregular heartbeat.
  • Serious Allergic Reaction: Difficulty breathing, difficulty breathing, skin rash, swollen tongue or throat are signs of anaphylaxis , a life-threatening condition.
  • Low blood pressure
  • Harm to the fetus

Inform your doctor of any side effects and, if you have an allergic reaction, seek emergency medical attention.

Warnings and interactions

Black box warning

The FDA has a black box warning (the strongest warning the agency publishes on its labels) regarding losartan due to fetal toxicity. Stop taking this medicine (also known as Cozaar) or any medicine that contains losartan, such as Hyzaar, as soon as a pregnancy is detected .

Possible drug interactions

Also, the following medicines can interfere with how losartan works, so tell your doctor if you are also taking:

  • Other blood pressure medications, including aliskiren, enalapril, captopril, lisinopril, or ramipril.
  • Non-steroidal anti-inflammatory drugs (NSAIDs) pain relievers such as ibuprofen, naproxen, diclofenac, celecoxib, or etoricoxib.
  • More than 3 grams of aspirin a day
  • Potassium supplements or salt substitutes that contain potassium.
  • Spironolactone and other diuretics (water tablets)
  • Anticoagulant heparin
  • Lithium psychiatric drug


Losartan was among a series of drugs that were recalled by the FDA between 2018 and 2020 because they were found to contain unacceptably high levels of nitrosamine, a potentially carcinogenic substance . Impurities are believed to have been introduced into the manufacturing process.

The FDA has a list of ARB recalls that you can check to see if any of the recalled lots have any vials of losartan in their medicine cabinet.

In the meantime, the FDA recommends not to stop taking the drug, even if it is part of the recalled batches. Instead, inform your pharmacist so they can suggest a replacement or other treatment option. Not all losartan vials contain impurities, so you can find an option that does not contain impurities .

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