Losartan: What Is It and What's It Used For?

Losartan is a drug from the family of angiotensin II receptor blockers. It's used to control blood pressure levels and possible complications. Today we'll tell you everything you should know about it.
Losartan: What Is It and What's It Used For?

Last update: 21 June, 2021

Losartan, marketed under the names Cozaar, Soluvass or Fortzaar, is a drug approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) as a safe treatment for high blood pressure. Although it doesn’t cure the disease, it does help to counteract its symptoms and adverse effects.

Its effects have been shown to be comparable with those of other drugs such as atenolol, nifedipine, felodipine, captopril, or enalapril. Because of this, it’s a very suitable alternative when someone has problems ingesting any of these drugs. Today, we’re going to look at all you need to know about this medication: how it works, side effects, dosage, and recommendations.

What is losartan used for?

Losartan is used for high blood pressure
Losartan is one of the most commonly used drugs for treating cardiovascular problems, especially high blood pressure.

Losartan is a medication that belongs to the group of angiotensin II receptor blockers. Evidence indicates that drugs of this type are effective in regulating blood pressure, preventing damage to target organs, promoting vascular remodeling, protecting heart and kidney function, and offering benefits in endothelial dysfunction.

Angiotensin is a natural chemical in our bodies that narrows the walls of the blood vessels. When this happens, there’s greater resistance to blood circulation, which can then lead to hypertension. Losartan and other drugs work by blocking this hormone, allowing blood vessels to dilate.

Its usefulness as a treatment for left ventricular hypertrophy has also been proven. This condition, popularly known as an enlarged heart, can be caused as a consequence of hypertension.

The mechanism under which this drug operates has been studied in this report. Experts have shown that it absorbs rapidly, with maximum concentrations between one and two hours after ingestion. Once in the body, 14 percent of the compound is metabolized as E 3174. On average, it’s 10 to 40 times more potent than the parent substance. Its effects last an average of 24 hours, depending on the dosage.

Although it acts immediately, vascular regulation and the protection of the target organs are generally achieved during the first week and reach their maximum levels around the sixth week of treatment. This is proven by this report, which also suggests that the reduction in tension caused by its use ranges from 8 mmHg to 13 mmHg.

How to take losartan

This medication can be prescribed on its own, or alongside other antihypertensives. The specialist will choose what’s best, according to how well the patient tolerates the active ingredient. In general, a change in diet isn’t necessary to maximize its assimilation, except for the reduction of sodium levels that is quite usual among hypertensive patients.


Manufacturers market it in 12.5, 50, and 100-milligram tablets. The dose adjustment is carried out with the help of a pill cutter if a smaller dosage is required. You can also combine the different formats to get the right dosage.


As indicated by the European Medicines Agency (EMA), the suggested dose for an adult is 50 milligrams, once a day, although, in some contexts, the specialist may use 100 milligrams if the body is resistant to its effects. It’s generally better to take the medication in the morning.

As there hasn’t been enough research in this regard, in children and young people a dose of 25 milligrams is suggested for groups ranging between 20-5o kilograms (44 to 110 lbs). Its use in children under 6 years should be avoided, in part due to not allowing what effects they could produce in them.

The actual dose varies according to the context, the patient’s conditions, and how it’s combined with other drugs. For example, the following conditions:

  • Heart failure: 12.5 milligrams per day, which is gradually increased according to tolerability.
  • Age over 75 years: 25 milligrams a day and increased according to tolerability and the reduction of symptoms.
  • Hypertension with left ventricular hypertrophy: It’s recommended to start with 5o milligrams a day and then progressively increase to 100 milligrams over the next two weeks.

The actual values will be determined by the physician, and they shouldn’t be adjusted by the patient. This is very important in order to avoid overdoses or interactions with other parallel treatment.

Who shouldn’t take losartan?

Although the drug is very well tolerated by the body, certain groups of patients should avoid taking it. We’re referring to the following:


Losartan is not used in pregnancy.
Due to the possible risks to pregnancy, authorized antihypertensive drugs are very scarce at this stage.

Many studies and investigations have indicated that medications belonging to angiotensin II blockers and inhibitors are not at all recommended during pregnancy. They shouldn’t be administered, regardless of the week of gestation, as there have been many instances of complications in the fetus. These include:

  • Pulmonary hypoplasia
  • Neonatal hypotension
  • Risk of perinatal death
  • Tubular abnormalities
  • Hypoplasia of the skull
  • Renal failure with oliguria and anuria
  • Fetal growth restriction

Although its intake is short-term, it should be avoided, as the adverse effects can be permanent. These are most common during the first trimester of pregnancy. Due to the lack of studies in this regard, losartan and the same family of medications should be avoided while breastfeeding, as other evidence suggests.

Interaction with other drugs

Diabetics taking aliskiren should avoid the use of losartan and other blockers because of possible adverse effects. The Food and Drug Administration (FDA) issued a statement a couple of years ago about the contraindications of this combination. Among the possible adverse effects we find the following:

  • Damage to kidney functioning
  • High levels of potassium in the blood (hyperkalemia)
  • Low blood pressure (hypotension)
  • Risks of cardiovascular diseases

This isn’t to say that diabetics can’t take losartan, simply that it should be avoided if the patient is already taking aliskiren-based treatment. Some medications that contain it are Valturna, Tekurna, Tekamlo, Amturnide and Tekturna HCT.

Liver injury or disease

Nor should the drug be administered if the patient has a liver condition, especially if it’s chronic. Studies indicate that losartan may be linked to liver problems, making the condition worse. In these cases, an alternative should be sought in order to control blood pressure levels.

What are the possible side effects?

Following the FDA bulletins regarding losartan, patients may experience the following side effects:

These are the most common effects. In rare cases, changes in potassium levels in the body, jaundice, constipation, gastritis, anxiety, loss of libido, urinary tract infections, sleep disorders, difficulty breathing, and others can develop. This only occurs in a very small percentage of the population.

Allergic reactions to the component are also possible. If you have hives, fever, and rashes, stop taking it and consult a specialist.

What happens if I miss a dose?

If you forget to take it at the correct time, you can take the dosage, but not if it’s nearly time for the next tablet. If there are fewer than 12 hours until your next dosage then it’s best to simply wait. This avoids excessive accumulations of the drug that can cause hypotensive episodes.

What should I do in the event of a losartan overdose?

The protocol here is to attend a medical center or specialist in order to evaluate possible side effects. Depending on the intake, a series of tests, examinations, or some medication will be administered to avoid syncope or abrupt drops in tension while the effects pass.

How to store or dispose of this medicine?

You should store this medication in a dry place, between 15 and 30 degrees Celsius. Although there’s no evidence of its deterioration due to direct sunlight, it’s best to avoid this. If you have to dispose of the drug, do so in a hermetically sealed bag.

Keep a record of the possible incidents that have occurred since the beginning of the treatment and share these with the specialist during your regular appointments. We also suggest that you monitor blood pressure in the coming months to assess its assimilation and effectiveness in counteracting vascular imbalances.

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