Losartan is an oral antihypertensive prescription drug, belongs to a class of medications known as angiotensin receptor blockers (ARBs). Losartan acts by blocking the action of angiotensin II (a natural substance) and thereby relaxing blood vessels to flow blood smoothly and helps the heart to pump more efficiently. It is available as the brand-name drug and generic drug. Generic drugs usually cost less.

What is Losartan potassium (Cozaar) used for?

Losartan either used alone or in combination with other drugs to relieve high blood pressure. Losartan can also reduce the risk of stroke in people who have high blood pressure, and in left ventricular hypertrophy (a condition in which walls of the left side of the heart get enlarged). It is also used to treat diabetic nephropathy (a kidney disease caused by diabetes), in type 2 diabetes.

How to use Losartan Potassium (Cozaar)?

The dose of the drug is based on your medical condition and response to treatment. Take this drug orally as directed by your doctor, usually once per day with or without food.

This drug comes with the medication guide read all the instruction carefully before you start taking losartan. If you have any query, discuss with your doctor or pharmacist.

Take the whole tablet with water or other liquids. Do not crush, break, or chew it. If you are using liquid form, shake the bottle well before each dose and use special measuring device/spoon.

Take this drug regularly even if you feel better to get the full benefit from it. Preferably take medicine at the same time each day to avoid confusion.

Talk to your doctor if your condition does not improve or if it gets worse (your blood pressure readings increase).

What are the side effects of Losartan Potassium (Cozaar)?

The commonly observed side effect with this drug is dizziness or lightheadedness (This effect occurs as your body gets adjusts to the medication). If any of these effects remain or get worse, talk to your doctor or pharmacist immediately. To lessen the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Get emergency medical assistance right away, if any of these severe side effects occur such as fainting, symptoms of hyperkalemia (high potassium blood level) like a slow/irregular heartbeat, muscle weakness.

This drug very rarely causes serious kidney problems or make them worse. Inform your doctor promptly, if you notice any signs of kidney problems like a change in the amount of urine

Allergic reaction to this medicine is very rare. However, get medical help promptly if you notice any symptoms of a severe allergic reaction, such as rash, itching/swelling (face/tongue/throat), breathlessness.

This is not a full record of all possible side effects. If you mark other effects not listed above, contact your doctor or pharmacist.

What are the precautions while using Losartan Potassium (Cozaar)?

Before using this drug, notify your doctor or pharmacist if you are allergic to it or if you have any other allergies.

Discuss with your doctor or pharmacist about medical history, mainly of liver disease, kidney problems, dehydration (severe loss of body water and minerals).

This medication may increase your blood potassium levels. Seek advice from your doctor before you use medicines, supplements, or salt substitutes that contain potassium.

Do not take alcoholic beverages until you have discussed with your doctor as alcohol may make the low blood pressure effect worse or increase the possibility of dizziness or fainting.

Do not take other medicines without consulting your doctor, primarily such as prescription or nonprescription (over-the-counter) medicines for asthma, colds, cough, hay fever, or sinus problems, and herbal or vitamin supplements.

The use of is this medicine is not recommended during pregnancy as it may harm to the fetus. Consult your doctor for further details.

It is not clear whether this drug can passes into breast milk. Consult your doctor before breastfeeding.

What are the drug interactions of Losartan Potassium (Cozaar)?

Losartan may interact with other medications, vitamins, or herbs you may be using. A drug interaction is when a substance changes the way a drug works which can be harmful or hinder the drug from working well.

Do not start, stop, or alter the dose of the drug without consulting your doctor as your doctor may be monitoring you for possible drug interactions.

Some products may interact with this drug such as lithium, aliskiren, drugs that may increase the blood level of potassium (like ACE inhibitors including lisinopril/benazepril, birth control pills containing drospirenone).

Some medications contain inactive ingredients that could raise your blood pressure or worsen your heart failure. Tell your doctor what products you are using, and ask how to use them safely (especially cough-and-cold products, diet aids, or NSAIDs like ibuprofen/naproxen).

This drug may cause low blood pressure, and the risk of low blood pressure is higher if you also take diuretics (water pills). Examples of diuretics include hydrochlorothiazide, furosemide, spironolactone.


Pregnancy: Using this drug while you are pregnant can cause serious (possibly fatal) harm to your unborn baby. Therefore, it is essential to use an effective form of birth control to keep from getting pregnant. Discuss with your doctor to use more reliable forms of birth control while taking this medication. If you think or you get pregnant while using this medicine, tell your doctor right away.

Children: The safety of this medicine is not established in children below six years.

Low blood pressure: Losartan may cause low blood pressure, which can make you feel faint or dizzy. If this occurs, inform your doctor right away.

Kidney problem: Taking losartan when your renin-angiotensin system is activated, it may damage your kidneys. This medication in people with kidney problems can make kidney disease worse.

What are the forms and strengths of Losartan Potassium (Cozaar)?

Generic: Losartan
Form: Oral tablet
Strengths: 25mg, 50mg, 100mg

Brand: Cozaar
Form: Oral tablet
Strengths: 25mg, 50mg, 100mg

What is the dosage of Losartan Potassium (Cozaar)?

Adult (18 to 64 years):

For Hypertension (high blood pressure):

Initial dose: 50mg once daily,
Dosage range: 25-100mg/day orally taken once or twice per day.

For Diabetic nephropathy:

Dose range: 50-100mg orally every day in people with type 2 diabetes and hypertension.

For Hypertension and Left Ventricular Hypertrophy:

Initial dose: 50mg orally every day, may be increased to 100mg every day; may be used in combination with a thiazide diuretic


Children (6 to 17 years):

The dose of the drug is based on your child’s weight.
Initial dose: 0.7mg/kg of body weight taken once per day.
Maximum dose: Not to exceed 1.4mg/kg/day (or 100mg/day).

Children (0 to 5 years):

Avoid using this drug in children below six years as safety and efficacy not established.


Older adults (65 years and above):

In older adults, the dose of the drug needs to be reduced, or given at different schedule. Because older adults eliminate drugs more slowly. This avoids the building of medicine in the body.

Most common questions asked about Losartan Potassium (Cozaar) / Q&A’s:

What are the most common side effects of Losartan Potassium (Cozaar)?

Most common side effects of Losartan are the common cold, stuffy nose, fatigue, dizziness, diarrhoea, hypoglycemia (low sugar level), a drop or rise in blood pressure, back pain and chest pain (infrequent). Typically, these side effects are mild and disappear within a few days. However, if the above side effects continue or they become severe, talk to your doctor at the earliest.

Does Losartan contain Valsartan?

No, both losartan and valsartan are different medicines. However, the only similarity between both the drugs is that both are classified as antihypertensive, angiotensin receptor blockers (ARBs). The difference between losartan and valsartan is in their structures, and that losartan is short-acting (shorter duration of action), and valsartan is long-acting (longer duration of action).

Is Valsartan the same as Losartan?

Valsartan and losartan are same when it comes to their classification, and they are different when it comes to their structure and duration of action, as losartan is short-acting (shorter duration of action), and valsartan is long-acting (longer duration of action).


TheMedPharma has made every effort to make sure that all the information is factually correct, comprehensive, and up-to-date. However, this website should not be considered as a substitute for the advice, knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or licensed health care professional before taking any medication. The drug information contained herein is subjected to changes if required. The lack of warnings or other information for a given drug does not mean that the drug or its combination is safe, effective or appropriate for use in all patients.