Losartan: Uses, Side Effects, and Drug Interactions

Research Based
Medically reviewed by - Dr. Abdul Khalique, MD Written by - Dr Qudsiya Raiees, MD


What is Losartan?

Losartan has been authorized by the FDA to treat an assortment of conditions, such as diabetic nephropathy and hypertension. Losartan 1Overview | Researched based study from National Institutes of Health belongs to the angiotensin II receptor blocker (ARB) medication class. Losartan oral tablet is sold as a brand-name drug and generic drug. The Brand name of Losartan is Cozaar. Losartan comes only in tablet form that can be taken by mouth.

Losartan belongs to the angiotensin II receptor blocker (ARB) medication class

How it works

How does losartan work?

  • Losartan is an Angiotensin II receptor blockers (ARBs) that inhibits the Angiotensin II hormone actions.
  • Angiotensin II promotes blood pressure control and maintains fluid balance.
  • Losartan lowers blood pressure and improves cardiovascular health by interfering with angiotensin II. 1How it works? | Researched based study from National Institutes of Health
  • The onset of action of losartan is around 6 hours and lasts for 24 hours

Angiotensin II Receptor Binding

  • Angiotensin II works by binding to angiotensin II receptors on blood vessels and other organs. Losartan inhibits only angiotensin II receptors.


  • Losartan prevents vasoconstriction by blocking the angiotensin receptor. Thus, blood vessels relax and dilate, thereby decreasing blood pressure.

Reduced Aldosterone Release

  • Losartan reduces fluid retention and aldosterone secretion by inhibiting angiotensin II.

Cardiovascular effects

  • Angiotensin II promotes heart muscle cell development and increases heart workload.
  • Losartan blocks angiotensin II, reducing cardiac strain and improving efficiency.


Uses of Losartan

Losartan is mostly used to treat hypertension, although it has other medicinal purposes. Here are losartan’s principal uses 1Uses | Researched based study from National Institutes of Health :

High Blood Pressure

  • Losartan is often used for hypertension. It lowers blood pressure and hypertension problems by relaxing blood arteries and lowering fluid retention.

Lowering Stroke Risk

  • Losartan and other blood pressure-lowering drugs may lessen stroke risk by avoiding brain blood vessel damage from high blood pressure.

Heart Failure

  • It promotes better heart pumping and minimizes heart failure symptoms including fluid retention and shortness of breath.

Diabetic Nephropathy

  • Losartan may treat proteinuria in type 2 diabetics with renal damage. It reduces proteinuria and filtration system pressure to preserve the kidneys.

Hypertensive Kidney Damage Prevention

  • Losartan may help reduce kidney damage in hypertensives, especially those at risk of diabetic nephropathy.

Migraine prevention

  • Studies show losartan may prevent migraines, but further study is required.


  • Losartan medication is used off-label for the treatment of stable coronary artery disease, intolerant to ACEIs, acute coronary syndrome, and Marfan syndrome.

Losartan must only be taken upon advice from a doctor and as per their instructions.

Side Effects

Side effects of Losartan.

Side Effects of Losartan

Like any medicine, losartan may have adverse effects. It’s crucial to remember that not all of these adverse effects are likely to happen, and if they do, you may need to see a doctor.

Common and least common adverse effects of losartan are:

Common Side Effects 1Side Effects | Researched based study from National Institutes of Health :

  • Headache
  • Dizziness
  • Fatigue
  • Back pain
  • Cough (less common than with angiotensin-converting enzyme inhibitors)
  • Urinary tract infection
  • Anemia.
  • Diarrhea
  • Sore throat
  • Upper respiratory infection (such as a cold)
  • Stuffy or runny nose

Less Common Side Effects:

  • Hypotension (low blood pressure)
  • Hyperkalemia (higher levels of blood potassium)
  • Orthostatic hypotension (immediate drop in blood pressure as soon as you stand)
  • Elevated blood urea nitrogen (BUN) and the levels of serum creatinine (markers of kidney dysfunction)
  • Cellulitis
  • Muscle pain or cramps
  • Gastrointestinal symptoms (such as nausea, gastritis. abdominal pain, diarrhea)
  • Allergic reactions (can include rash, swelling, severe dizziness, itching, difficulty breathing)
  • Kidney dysfunction
  • Elevated liver enzymes

Some Serious Side Effects are (Require Medical Attention):

  • Severe allergic reactions (e.g., difficulty breathing, swelling of the face, tongue, lips, or throat)
  • Chest pain or tightness
  • Signs of kidney issues (such as changes in urine output, swelling, rapid weight gain)
  • Irregular heartbeat
  • Signs of low blood pressure (dizziness, lightheadedness, fainting)
  • Edema
  • Persistent dry cough
  • Changes in vision
  • Symptoms of high potassium levels (such as muscle weakness or irregular heartbeat)

Always follow your doctor’s instructions and report any unusual symptoms or reactions to your healthcare provider.


Dosage & Strengths

The available strengths 2Dosage | Researched based study from Food and Drug Administration of Losartan tablet are

  • 25mg
  • 50mg
  • 100mg

Here are some common dosages for different uses: 

Hypertension (High Blood Pressure):

  • Starting dose: 50 mg once daily
  • Maintenance dose: 25 mg to 100 mg once daily

Diabetic Nephropathy (kidney disease) with Hypertension:

  • Starting dose: 50 mg once daily
  • Maintenance dose: 25 mg to 100 mg once daily

Heart Failure:

  • The Starting dose is: 25 mg once daily.
  • Maintenance dose: 50 mg or 100 mg once daily, as tolerated. 

The dosage will vary according to individuals. Always consult your doctor before trying out this medication. Dosages may be adjusted. Do not alter the dosage or quit taking losartan without consulting your healthcare provider, as sudden discontinuation can lead to rebound high blood pressure or other complications. 

Missed Dose:

  • Don’t miss a Losartan dosage. Consume the missed dosage as early as you recall.
  • Don’t take the missing dosage if it’s time for your next one. Never take two doses to make up for one that you missed.


  • Never exceed the recommended dosage. If you suspect a Losartan overdose, get in touch with your physician.

The Active ingredient is Losartan itself. While the inactive ingredients are Lactose monohydrate, Hypromellose, titanium dioxide, polyethylene glycol, povidone, hyprolose, cornstarch, microcrystalline Cellulose, etc.


How to Store Losartan?

  • Tablets of losartan should be kept at room temperature, which is usually between 20°C and 25°C (68°F and 77°F). 2Storage | Researched based study from Food and Drug Administration
  • Keep losartan in its original bottle and put it in a cool, dry place away from direct sunlight, heat, and moisture. Don’t put it in the bathroom or near the sink in the kitchen.
  • Keep losartan out of the reach of kids, infants and pets.
  • Do not put losartan in settings that are too cold or too hot, because this can change the efficacy of Losartan.


Risks & Precautions

Before taking losartan or any other medicine, it’s important to know about certain safety measures to make sure the medicine works and doesn’t hurt you. 2Risks & Precautions | Researched based study from Food and Drug Administration

Here are some things to think about before taking losartan:


  • Tell your doctor if you are allergic to any medicines, including losartan. Allergic responses can be as mild as spots on the skin or as serious as trouble breathing.


  • Losartan is contraindicated in pregnancy. It is harmful especially during the second and third trimesters.
  • Taking losartan during the first, second, and third trimesters of pregnancy can cause major harm to the growing fetus, such as decreased kidney function, low amounts of amniotic fluid (oligohydramnios), slowed bone growth, and even death of the fetus.
  • If you are pregnant or planning to conceive anytime soon, then ask your doctor about how to control your blood pressure. If you’re already using losartan and you get pregnant or conceive, then don’t stop taking it immediately without discussing it with your doctor first.


  • Losartan is contraindicated in breastfeeding also
  • Losartan and its byproducts are known to be passed out of the body in breast milk.
  • Since babies who are breastfed could be hurt by losartan, most doctors tell breastfeeding women not to take it. If you are planning to breastfeed while on losartan, talk to your doctor about the risks and benefits.

Kidney dysfunction

  • The kidneys get rid of most of the drug losartan. If your kidneys don’t work as well as they should, your doctor may need to change the dose or closely watch how the medicine affects you.

Liver Function

  • Tell your doctor if you’ve ever had liver disease or if your liver function tests are abnormal.
  • Losartan is broken down by the liver, so people with poor liver function may need to change their dose.

Levels of potassium

  • Losartan has the potential to raise the potassium levels in the blood.
  • Your doctor should check your potassium levels while you are on losartan if you have kidney problems, take potassium supplements, or eat a lot of potassium-rich foods.


  • When you stand up quickly after taking Losartan, your blood pressure can drop. This can make you feel ill or cause black out.
  • If you want to avoid orthostatic hypotension, stand up slowly from sitting or lying down position.


  • Losartan may alter the levels of sugar in your blood, so if you have diabetes, you should keep a close eye on your blood sugar and talk to your doctor if you notice any big changes.

During surgery

  • If you are going to have surgery, make sure your doctor knows you are taking losartan, because it may combine with the anesthesia and other drugs used during surgery.


  • Losartan can make you feel lightheaded or sleepy. Be careful when you drive or use heavy equipment until you understand how the medicine affects you.

Always do what your doctor tells you to do and be honest about your medical background and any worries you may have before you start taking losartan or while you are taking it. Your doctor will decide if losartan is a good choice for you based on your situation and health history.


Drugs that can interact with Losartan

Before starting losartan, it is necessary to let your doctor know about all of the drugs, herbal items, supplements and vitamins 3Interactions | Researched based study from The National Health Service that you are taking. Here are a few noteworthy interactions between losartan and drugs:

Potassium sparing diuretics (e.g., Spironolactone)

  • This will lead to rise in potassium levels of blood (hyperkalemia)


  • Losartan may raise blood levels of digoxin (used for management of cardiovascular diseases)

Inducers or Inhibitors of CYP2C9

  • The CYP2C9 enzyme breaks down losartan. Drugs that cause or inhibit this enzyme will have an impact on the body’s losartan levels.

Potassium Supplements or Salt Substitutes

  • Taking potassium supplements while on losartan will significantly elevate the risk of hyperkalemia.


  • When combined with Losartan, NSAIDs like ibuprofen and naproxen may worsen renal issues in addition to decreasing the efficiency of losartan. 2Interactions | Researched based study from Food and Drug Administration


  • Losartan may decrease the elimination of lithium, which might lead to an increase in blood lithium levels. 2Interactions | Researched based study from Food and Drug Administration

Anti diabetic drugs (such as insulin and oral hypoglycemic agents)

  • Blood sugar levels may be impacted by losartan, therefore changes in the dose of antidiabetic medication may be required.

Specific Antihypertensive Drugs

  • Combining losartan with other blood pressure-reducing drugs, particularly those that have comparable mechanisms of action (such as additional ACE inhibitors or ARBs), may have increased effects on decreasing blood pressure.


  • The antibiotic rifampin, which is used to treat tuberculosis, has the ability to lower the body’s levels of losartan.


  • Losartan and alcohol together may make you more susceptible to lightheadedness or sleepiness.

Before beginning, stopping, or altering the dose of any medicine, be sure to speak with your healthcare professional. They’ll assist in making sure your drug schedule is both efficient and safe.

Dietary Changes

Dietary changes while using Losartan

Losartan should be used with a nutritious diet to promote cardiovascular health and regulate blood pressure. Losartan patients should follow these diet guidelines:

Lower sodium intake

  • High blood pressure may result from salt overload. Limit processed foods, canned soups, salty snacks, and fast-food meals since they are rich in sodium.

Eat more potassium-rich foods

  • Since potassium is essential for heart and muscle function, you should still eat potassium-rich meals. Potassium-rich foods include bananas, potatoes, spinach, oranges, beans, and yogurt.

Eat fruits and vegetables

  • Vitamins, minerals, fiber, and antioxidants in these foods improve heart health. Add fruits and veggies in your regular diet.

Choose Lean Proteins

  • Choose lean proteins including chicken, fish, beans, lentils, and tofu. Cut down on red and processed meats.

Whole Grains

  • Choose brown rice, quinoa, whole wheat pasta, and whole-grain bread over processed grains.

Healthy Fats

  • Avocados, nuts, seeds, and olive oil. Rich Fats like these enhance heart health.

Limit Saturated and Trans Fats

  • Reduce saturated and trans fats in fried meals, fatty meats, full-fat dairy, and processed foods.

Low-Fat Dairy

  • Choose to eat low-fat or fat-free dairy to lower fats (saturated).

Portion Control

  • Watch your portions to lose weight and save calories.

Limit added sugars:

  • Cut down on sugary drinks, sweets, and desserts. Fruits provide natural sweetness.

Stay Hydrated:

  • Drink enough water daily to stay healthy.



Losartan that has shown to be very effective at treating high blood pressure, lowering the risk of heart problems, and slowing the development of kidney diseases. Losartan might have uses other than for the heart and blood vessels. Some studies have looked at how it protects people with diabetes from kidney damage and how it might help stop scar tissue from forming in different organs. As with any drug, Losartan could have side effects or combine with other drugs. Because of this, it’s important for people to talk to their doctors before starting or stopping any drug prescription.

Disclaimer: The user acknowledges that this article's information is being offered for informational purposes only. Every attempt has been made to guarantee that the article is informational and correct. If they have any doubts or questions about their health, we firmly advise our readers to visit a doctor or other healthcare professional.

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