Losartan Potassium

Pronunciation: (loe-SAR-tan).

Generic name
losartan potassium
Drug class
Cardio-Metabolic

Availability and supply rules vary by country

Trade names by country: United States · Canada

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What losartan potassium is and how it works

Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.

Mechanism of action: how losartan potassium works

Losartan selectively blocks the binding of angiotensin II to the AT1 receptor in vascular smooth muscle and the adrenal gland. This inhibition prevents vasoconstriction and aldosterone-mediated sodium and water retention, resulting in decreased blood pressure and reduced cardiac workload. Losartan does not inhibit ACE or increase bradykinin, minimizing cough risk.

What losartan potassium is used for

Hypertension (high blood pressure), in adults and children 6 years and older.

Hypertension (high blood pressure), in adults and children 6 years and older. (2)

Diabetic nephropathy — treatment of kidney disease (elevated serum creatinine and protein in the urine) in people with type 2 diabetes and a history of high blood pressure.

Diabetic nephropathy — treatment of kidney disease (elevated serum creatinine and protein in the urine) in people with type 2 diabetes and a history of high blood pressure. (2)

Reduction of the risk of stroke in patients with hypertension and left ventricular hypertrophy (an enlarged heart-muscle wall). The label notes this specific stroke-risk-reduction benefit was not shown to apply to Black patients.

Reduction of the risk of stroke in patients with hypertension and left ventricular hypertrophy (an enlarged heart-muscle wall). The label notes this specific stroke-risk-reduction benefit was not shown to apply to Black patients. (2)

Before taking losartan potassium

Do not take / not appropriate for

  • Contraindicated in pregnancy (especially 2nd/3rd trimester), known hypersensitivity, and severe hepatic impairment. (Contraindication) (2)

Tell your clinician about

(2)

How to take losartan potassium

  • General Instructions: Take losartan by mouth, with or without food, as directed by your healthcare provider. Take it at the same time each day.. Adult Dosing: The usual starting dose for adults with hypertension is 50 mg once daily. The dose may be increased to 100 mg once daily based on response.. Pediatric Dosing: For children 6 years and older: starting dose is 0.7 mg/kg once daily (up to 50 mg total).. Administration: Swallow the tablet whole with water. Do not crush or chew.. When To Stop: Do not stop taking losartan without consulting your doctor, even if you feel well.. Storage: Store at room temperature, away from moisture and heat.
  • This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.
(2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (2)

Missed dose

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose. Do not take an extra dose to make up for the one you missed.

Overdose

Symptoms of overdose may include severe dizziness, fainting, or a very slow or fast heartbeat. Seek emergency medical attention or call your local poison control center immediately. (2)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.

Dizziness

Incidence: Common (incidence >=2% and greater than placebo)

Upper respiratory infection / nasal congestion

Incidence: Common (incidence >=2% and greater than placebo)

Back pain

Incidence: Common (incidence >=2% and greater than placebo)

Fatigue, or mild cough

Incidence: Reported; exact frequency not established in the sources reviewed

Symptoms of high potassium (hyperkalemia) — muscle weakness, irregular heartbeat, or tingling — or of low blood pressure — severe dizziness or fainting, especially in people who are dehydrated

Incidence: Uncommon; monitored with periodic blood tests

Reduced urination, swelling, or other signs of worsening kidney function

Incidence: Uncommon; higher risk with pre-existing kidney disease

Swelling of the face, lips, tongue, or throat, or difficulty breathing (angioedema) — a medical emergency

Incidence: Rare

Serious warnings

BOXED WARNING — FETAL TOXICITY — serious

Symptoms: BOXED WARNING — FETAL TOXICITY: losartan can cause injury and death to a developing fetus when used during pregnancy, especially in the second and third trimester. Anyone who becomes pregnant while taking losartan should contact their clinician right away so the medicine can be reassessed as soon as possible.

Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)

May cause kidney problems, especially in patients with pre-existing kidney disease, and can raise blood potassium levels (hyperkalemia) — serious

Symptoms: May cause kidney problems, especially in patients with pre-existing kidney disease, and can raise blood potassium levels (hyperkalemia); periodic blood tests are used to monitor both. May cause symptomatic low blood pressure, especially in people who are dehydrated or volume-depleted.

Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)

Contraindications on the current FDA label — serious

Symptoms: Contraindications on the current FDA label: known hypersensitivity to losartan or any component of the tablet; combined use with aliskiren in people with diabetes. Precautions recorded in the clinician database: extra caution in people with renal artery stenosis, volume depletion, concurrent potassium-sparing agents, or liver impairment (a reduced starting dose of 25 mg once daily is used for mild-to-moderate liver impairment; losartan has not been studied in severe liver impairment).

Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)

Interactions

Medicine or testEffectAction
Potassium-sparing diuretics or potassium supplementsIncreased risk of high blood potassium (hyperkalemia); periodic potassium monitoring is used. (2)
NSAIDs (e.g., ibuprofen, naproxen)May reduce losartan's blood-pressure-lowering effect and can worsen kidney function, particularly in people who are older or dehydrated. (2)
LithiumLosartan can increase lithium levels and the risk of lithium toxicity; lithium levels are monitored if the two are used together. (2)
ACE inhibitors or aliskiren (dual blockade of the renin-angiotensin system)Combining losartan with an ACE inhibitor or aliskiren increases the risk of low blood pressure, fainting, high potassium, and changes in kidney function; this combination is generally avoided, and is contraindicated with aliskiren in people with diabetes. (2)
Other antihypertensive medicinesAdditive blood-pressure-lowering effect; often used intentionally together under a clinician's guidance, but combinations are monitored for excessive blood pressure drops.

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Losartan can cause fetal injury or death when used during pregnancy, especially in the second and third trimester (see boxed warning). Anyone who becomes pregnant while taking losartan should contact their clinician as soon as possible so the medicine can be reassessed. (2)

Breastfeeding

It is not known whether losartan passes into human breast milk, but losartan and its active breakdown product were found at significant levels in the milk of nursing animals in studies. Discuss breastfeeding plans with a clinician, who can weigh the theoretical risk against the benefits of continuing losartan. (2)

Children

For hypertension in children 6 years and older, the usual starting dose is 0.7 mg/kg once daily, up to a 50 mg total maximum; doses above 1.4 mg/kg/day or 100 mg/day have not been studied. Losartan is not recommended for children under 6 years old or for children with a glomerular filtration rate under 30 mL/min/1.73m2. (2)

Renal_impairment

Renal impairment: used with monitoring of kidney function and potassium; children with GFR under 30 mL/min/1.73m2 are not recommended to use losartan. Hepatic impairment: a reduced starting dose of 25 mg once daily is used for mild-to-moderate liver impairment; losartan has not been studied in severe liver impairment, so it is used with added caution in that setting. (2)

Hepatic_impairment

Renal impairment: used with monitoring of kidney function and potassium; children with GFR under 30 mL/min/1.73m2 are not recommended to use losartan. Hepatic impairment: a reduced starting dose of 25 mg once daily is used for mild-to-moderate liver impairment; losartan has not been studied in severe liver impairment, so it is used with added caution in that setting. (2)

Monitoring

(2)

Storage

Store at 25 degC (77 degF); brief excursions between 15-30 degC (59-86 degF) are permitted during transport or short periods. Keep the container tightly closed and protect from light.

Professional information

Clinician-facing context only. This section does not replace current product labeling.

General (US label)

Indication: Hypertension / diabetic nephropathy / stroke-risk reduction

Dose summary: Initial dose of 50 mg once daily. May titrate to 100 mg once daily based on blood pressure response. Hepatic impairment: start at 25 mg once daily for mild-to-moderate impairment.

Renal context: No specific renal-impairment dose reduction table is published for adults with reduced GFR; general caution and monitoring of kidney function and potassium apply. In children, losartan is not recommended if GFR is under 30 mL/min/1.73m2. (2)

Mechanism of action

Frequently asked questions

How long does it take for losartan to lower blood pressure?

Most people begin to see a reduction in blood pressure within 1 week, with the full effect typically seen in 3–6 weeks.

Can I take losartan if I am pregnant or breastfeeding?

Losartan should not be used during pregnancy, especially in the second and third trimesters, due to risk of harm to the unborn baby. Consult your doctor if you are breastfeeding.

What should I do if I experience dizziness while taking losartan?

Dizziness is a common side effect, especially when starting treatment. Stand up slowly from sitting or lying positions. If dizziness persists or worsens, contact your healthcare provider.

Can losartan be taken with other blood pressure medications?

Yes, losartan is often combined with other antihypertensive agents, such as diuretics or calcium channel blockers, for better blood pressure control. Always follow your doctor's instructions.

Does losartan affect potassium levels?

Yes, losartan can increase potassium levels in the blood. Your doctor may monitor your potassium and advise you to avoid potassium-rich foods or supplements.

Is losartan safe for people with kidney disease?

Losartan is often used to protect the kidneys in people with diabetes and proteinuria, but dose adjustments may be needed in patients with kidney impairment. Regular monitoring is important.

What foods or drinks should I avoid while taking losartan?

Avoid salt substitutes containing potassium and limit high-potassium foods. Alcohol should be limited as it can increase side effects.

What is losartan used for?

Losartan is FDA-approved to treat high blood pressure (hypertension), to help protect the kidneys in people with type 2 diabetes who have protein in their urine (diabetic nephropathy), and to reduce the risk of stroke in patients with high blood pressure and an enlarged heart-muscle wall (left ventricular hypertrophy). Heart failure is not an FDA-approved use of losartan.

What class of drug is losartan?

Losartan belongs to a class of medications called angiotensin II receptor blockers (ARBs). It works by blocking the action of angiotensin II, a substance in the body that causes blood vessels to tighten and narrow, thereby lowering blood pressure and improving blood flow.

What are the most common side effects of losartan?

The most common side effects of losartan include dizziness, lightheadedness (especially when standing up), upper respiratory infections (cold symptoms), fatigue, and back pain. Most people tolerate losartan well, and many experience no side effects at all. These side effects are generally mild and often improve as your body adjusts to the medication.

Can you take Sudafed with losartan?

Use caution when taking Sudafed (pseudoephedrine) with losartan. Sudafed can increase blood pressure and may counteract losartan's blood pressure-lowering effects. If you need a decongestant, consider alternatives like steroid nasal sprays (Flonase) or consult your doctor. If you must use Sudafed, monitor your blood pressure closely and use the lowest effective dose for the shortest duration.

What allergy medicine can I take with losartan?

Safe allergy medications to take with losartan include non-sedating antihistamines like Claritin (loratadine), Zyrtec (cetirizine), and Allegra (fexofenadine). Nasal corticosteroid sprays like Flonase are also safe and effective. Avoid combination allergy products containing decongestants (like pseudoephedrine or phenylephrine) as these can raise blood pressure and reduce losartan's effectiveness.

Can I take Claritin with losartan?

Yes, Claritin (loratadine) is generally safe to take with losartan. Claritin is a non-sedating antihistamine that does not significantly interact with losartan or affect blood pressure control. No dose adjustments are needed, and this combination is safe for long-term use. As always, inform your doctor about all medications you're taking.

Can I take Zyrtec with losartan?

Yes, Zyrtec (cetirizine) is generally safe to take with losartan. Like Claritin, Zyrtec does not significantly interact with losartan and does not affect blood pressure. It may cause mild drowsiness in some people. This is a safe combination for most patients managing both allergies and high blood pressure.

What anti-inflammatory medicine can I take with losartan?

The preferred pain reliever with losartan is acetaminophen (Tylenol), which does not affect blood pressure or kidney function. Use NSAIDs (ibuprofen, naproxen, aspirin) with caution as they can reduce losartan's effectiveness and increase kidney stress. If NSAIDs are necessary, use the lowest effective dose for the shortest time and have your doctor monitor your kidney function and blood pressure.

Should losartan be taken in the morning or at night?

Losartan can be taken at any time of day, with or without food. The most important thing is to take it at the same time each day for consistency. Some people prefer morning dosing to avoid nighttime bathroom trips if combined with a diuretic. Others take it at night if they experience dizziness. Discuss with your doctor which timing works best for your lifestyle and symptom pattern.

What is the difference between losartan and Cozaar?

There is no difference - Cozaar is simply the brand name for losartan. Losartan is the generic name of the medication. Generic losartan contains the same active ingredient, works the same way, and is just as effective as brand-name Cozaar, but is typically much less expensive. The FDA requires generic medications to meet the same quality and safety standards as brand-name drugs.

Can losartan cause weight gain?

Weight gain is not a common side effect of losartan. In fact, unlike some older blood pressure medications (like beta-blockers), ARBs like losartan are generally weight-neutral. If you experience sudden weight gain while taking losartan, especially if accompanied by swelling in your legs or shortness of breath, contact your doctor immediately as this could indicate fluid retention or heart problems.

Is it safe to stop taking losartan suddenly?

Do not stop taking losartan suddenly without consulting your doctor. While losartan doesn't typically cause severe withdrawal symptoms, stopping abruptly can cause your blood pressure to spike rapidly, potentially leading to serious complications like heart attack or stroke. If you need to stop losartan, your doctor will create a tapering plan and may prescribe an alternative medication to maintain blood pressure control.

Can I drink alcohol while taking losartan?

You can drink alcohol in moderation while taking losartan, but be cautious. Alcohol can enhance losartan's blood pressure-lowering effect, potentially causing excessive drops in blood pressure, dizziness, and lightheadedness. Limit alcohol to moderate amounts (no more than 1-2 drinks per day for men, 1 drink for women), and avoid binge drinking. If you feel dizzy or lightheaded after drinking, sit or lie down immediately.

What happens if I take too much Losartan?

Taking too much Losartan can lead to symptoms such as severe dizziness, fainting, and a dangerously low heart rate. In cases of suspected overdose, it is crucial to seek immediate emergency medical attention. Do not attempt to self-treat an overdose. Prompt medical evaluation and intervention are necessary to manage potential complications and ensure patient safety.

Is Losartan safe during pregnancy?

No — losartan carries an FDA boxed warning for fetal toxicity. It can cause injury and death to a developing fetus, especially when used during the second and third trimesters. It is imperative to contact your doctor immediately if you are pregnant, planning to become pregnant, or breastfeeding while taking losartan, so the medicine can be reassessed and alternative treatments discussed.

What is the mechanism of action of losartan potassium?

Losartan selectively blocks the binding of angiotensin II to the AT1 receptor in vascular smooth muscle and the adrenal gland. This inhibition prevents vasoconstriction and aldosterone-mediated sodium and water retention, resulting in decreased blood pressure and reduced cardiac workload. Losartan does not inhibit ACE or increase bradykinin, minimizing cough risk.

What is the generic name of Losartan Potassium?

The generic name is losartan potassium.

What class of drug is losartan potassium?

Losartan Potassium is classed as: Cardio-Metabolic.

References

  1. Losartan clinician-authored medicine recordMedGuideGlobal · Global · accessed 2026-08-06 · source 1
  2. COZAAR (losartan potassium) tablet — prescribing informationU.S. National Library of Medicine, DailyMed · United States · accessed 2026-08-06 · source 2
  3. LOSARTAN POTASSIUM TABLET [REMEDYREPACK INC.] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 3
  4. Losartan — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 4
  5. Losartan Potassium — FDA approval record (Drugs@FDA ANDA078243)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 5
  6. losartan — RxNorm normalized drug concept (RXCUI 52175)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 6

Brand names by country

Single-ingredient losartan potassium names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Losortan Potassium25 mg, 50 mg, 100 mg · preferred pharmaceuticals inc.
  • COZAAR50 mg, 100 mg, 25 mg · organon llc
  • ARBLI10 mg/mL · scienture llc

Canada

  • COZAAR
View brands in additional countries.

General information only — not a diagnosis, prescription, or substitute for professional medical advice.

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