Angiotensin II Receptor Blocker (ARB)Not Controlled

Cozaar®

Losartan Potassium

Generic (originally Merck)·FDA 1995·
25mg50mg100mg

Version 2025-04 · Last reviewed April 1, 2025 · Methodology

List Price

$40

With Insurance

$4-10

The Short Version

Plain-language summary

Cozaar (Losartan Potassium) blocks a hormone that tightens blood vessels and raises blood pressure. It also protects the kidneys, which is why it's commonly prescribed for people with diabetes.

How it works: Losartan blocks the angiotensin II type 1 (AT1) receptor — the receptor responsible for the blood pressure-raising effects of angiotensin II. Unlike ACE inhibitors (which block the enzyme that produces angiotensin II), ARBs block the receptor where angiotensin II acts. This means angiotensin II is still produced but cannot exert its effects.

What people most commonly report

Upper respiratory infection
8%
Dizziness
3-4%
Back pain
2%
Fatigue
2-4%
Diarrhea
2%

Reported in trials but may not be causally related

Most studies were paid for by the company that makes this drug.

What Else the Evidence Supports

Non-drug options with clinical backing

The same lifestyle interventions that work for all blood pressure medications apply here. Weight loss, dietary changes, exercise, and alcohol reduction can produce blood pressure reductions comparable to losartan in many patients.

Weight lossEmerging

Approximately −1 mmHg systolic per kg lost.

DASH diet patternEmerging

−8 to −14 mmHg systolic in hypertensive patients.

Aerobic exerciseEmerging

−5 to −8 mmHg systolic.

Alcohol reductionEmerging

−4 to −7 mmHg when reducing from moderate to low/none.

What This Really Costs

Long-term cost projection based on current pricing

Monthly

$18

$7 w/ insurance

without insurance

Annual

$216

$84 w/ insurance

without insurance

10 Years

$2.2K

$840 w/ insurance

without insurance

30 Years

$6.5K

$2.5K w/ insurance

without insurance

Lifestyle alternative: $0/month in prescriptions. Weight lossApproximately −1 mmHg systolic per kg lost.

The average American retiree spends $165,000 on healthcare after retirement (Fidelity, 2024). Informed choices today compound over decades.

Related Evidence

Explore related medications reviewed on EvidentMeds

Metabolic & Lifestyle Alternatives

Lifestyle Approaches for Blood Pressure

The same lifestyle interventions that work for all blood pressure medications apply here. Weight loss, dietary changes, exercise, and alcohol reduction can produce blood pressure reductions comparable to losartan in many patients.

Important context: Evidence quality varies across these approaches. Some are well-studied with randomized controlled trial data; others are based on observational or smaller studies. These interventions are not guaranteed to replace medication for all patients. Discuss with your doctor whether any of these are appropriate for your clinical situation.

Global Prescribing & Pricing

Losartan is one of the most prescribed ARBs globally; widely used as a first-line antihypertensive

🇺🇸

United States

$25-50/mo

Rate

Most prescribed ARB; often substituted for ACE inhibitors due to no cough

Policy

No lifestyle prerequisite

Cover

Usually covered

🇬🇧

United Kingdom

~$2-5/mo

Rate

NICE alternative to ACE inhibitors when cough is an issue

Policy

Lifestyle advice required alongside prescribing

Cover

Fully covered by NHS

🇫🇷

France

~$3-8/mo

Rate

First-line alternative to ACE inhibitors

Policy

Lifestyle counseling part of care pathway

Cover

Covered by Sécurité Sociale

🇩🇪

Germany

~$4-10/mo

Rate

Widely prescribed first-line ARB

Policy

Lifestyle emphasis per DHL guidelines

Cover

Covered by GKV

🇯🇵

Japan

~$15-30/mo

Rate

ARBs are preferred over ACE inhibitors in Japan — losartan widely used

Policy

Salt reduction programs widely promoted

Cover

Covered by JHIS

Losartan is functionally equivalent to lisinopril for most patients — without the cough. The US charges $25-50/month for a drug that costs $2-5 in the UK. Both drugs lower blood pressure equally; the main advantage of an ARB is tolerability.

Clinical Trials & Funding

Understanding who funds research helps contextualize results. Industry-funded trials are not automatically invalid — they undergo the same FDA review — but declared conflicts and sponsor effects are worth knowing. All linked trials can be verified on ClinicalTrials.gov.

Key Efficacy Results

LIFE: 13% reduction in primary composite endpoint vs atenolol; 25% stroke reduction. RENAAL: 16% reduction in doubling of serum creatinine in diabetic nephropathy.

Referenced Studies

Each study shows its evidence level and Cochrane RoB-2 risk-of-bias rating — tap the bias badge for details.

Evidence & Transparency

Cochrane RoB-2 (Risk of Bias)

Badges reflect an editorial assessment using Cochrane's RoB-2 tool domains: randomization, intervention deviation, missing data, outcome measurement, and selective reporting. These are not certified Cochrane reviews. Learn more ↗

CMS Open Payments

Manufacturer payment disclosures are reported via the CMS Sunshine Act. Disclosure is legally required and does not imply bias or misconduct. Language uses "may," "suggests," or "appears" — never definitive clinical claims. CMS Open Payments ↗

Live Clinical Trials

Live from ClinicalTrials.gov · refreshed every 4 hours

Currently enrolling, active, and recently completed studies involving Losartan Potassium. Data is pulled directly from the U.S. National Library of Medicine.

Recent Research

Live from PubMed · peer-reviewed literature · refreshed every 4 hours

Most recently indexed clinical trials and systematic reviews mentioning Losartan Potassium in PubMed.

Source Documentation

Structured citations for referenced clinical trials

Each referenced trial is listed with its registry ID, funding source, and bias assessment. Use the copy button to generate a formatted citation.

TrialRegistry IDCite
LIFE (Merck)NCT00338260
RENAAL (Merck)NCT00308347

Bias ratings use Cochrane RoB-2 methodology. Editorial assessment — not a certified Cochrane review.

Our Methodology

Common Side Effects

While taking this medication, you may experience the following common side effects. We've included tips on how to manage them.

Dizziness

3-4%

Rise slowly; most common when starting or increasing dose

Upper respiratory infection

8%

Reported in trials but may not be causally related

Back pain

2%

Usually mild; tell your doctor if persistent

Fatigue

2-4%

Often improves as body adjusts

Diarrhea

2%

Usually mild; stay hydrated

Nasal congestion

2%

Usually mild and self-limiting

High potassium

1-5%

Avoid potassium supplements and salt substitutes

Serious Adverse Effects

  • Angioedema (rare — less common than with ACE inhibitors but still possible)
  • Acute kidney failure (especially with dehydration or NSAIDs)
  • Hyperkalemia (dangerous potassium levels)
  • Severe hypotension (especially in volume-depleted patients)

Drug Interactions

Major Interactions (Avoid)

Potassium supplements / potassium-sparing diureticsDangerous hyperkalemia — monitor potassium closely
ACE inhibitors (lisinopril)Dual RAAS blockade increases kidney failure and hyperkalemia — avoid combining
Aliskiren (in diabetic patients)Contraindicated — increased renal impairment and hypotension

Moderate Interactions (Caution)

NSAIDs (ibuprofen, naproxen)Reduces blood pressure effect; increases kidney injury risk
LithiumIncreases lithium levels — monitor closely
FluconazoleInhibits conversion of losartan to active metabolite — may reduce effectiveness

Food Interactions

Salt substitutes (KCl)Risk of high potassium — avoid
AlcoholAdditive blood pressure lowering

When to Contact Your Doctor

This medication requires ongoing medical supervision. The following situations warrant a prompt conversation with your prescribing physician — do not wait for your next scheduled appointment.

Contact soon if you notice

  • Angioedema (rare — less common than with ACE inhibitors but still possible)
  • Acute kidney failure (especially with dehydration or NSAIDs)
  • Hyperkalemia (dangerous potassium levels)
  • Severe hypotension (especially in volume-depleted patients)
  • Blood pressure rising above 140/90 mmHg

Also discuss if you want to

  • Review whether this medication is still appropriate for you
  • Consider dosage adjustments based on response
  • Explore lifestyle or non-drug alternatives
  • Understand stopping or tapering options
  • Plan monitoring labs and follow-up

In the US, call 911 or go to the nearest emergency room for severe symptoms. Poison Control: 1-800-222-1222.

Special Populations

Safety classifications for specific groups — discuss with your provider before use.

ContraindicatedPregnancy

Category D. Causes fetal kidney damage, oligohydramnios, and death in 2nd/3rd trimester. Discontinue immediately if pregnancy is detected.

Not RecommendedBreastfeeding

Unknown if excreted in milk; potential for serious adverse effects in infant.

Blood Pressure Rises Post-MenopauseMenopause / Hormonal

Estrogen decline leads to vascular stiffness and rising blood pressure. Losartan is a common first-line choice for menopausal women who cannot tolerate ACE inhibitor cough. Ask whether hormonal evaluation should accompany your blood pressure workup.

Approved ≥6 yearsChildren & Teens

Approved for hypertension in children 6+ with GFR >30.

Use Standard DoseOlder Adults

No specific dose adjustment for age. Monitor renal function and potassium.

Adjust DoseKidney Disease

Use with caution in renal impairment. Monitor potassium and creatinine closely. Avoid if bilateral renal artery stenosis.

FDA Adverse Event Reports

Patient-filed reports from the FDA FAERS database · refreshed daily

Anecdotal data. Reports are not confirmed causation. Always consult your provider.

Community Reports

User-reported experiences — anonymous & anecdotal

Stopping This Medication Safely

Taper CautiouslyDocumented timeframe: 2-6 weeks minimum

Abrupt discontinuation can cause rebound hypertension. Blood pressure may rise significantly within days of stopping.

What Published Research Shows About Stopping This Medication

This summarizes what published research documents — it is not personal medical advice. Any changes to your medication require discussion with your prescribing physician.

  • ·Gradual dose reduction is preferred — 100mg → 50mg → 25mg every 1-2 weeks
  • ·Home blood pressure monitoring twice daily during taper is recommended
  • ·Building dietary and exercise habits before tapering improves success
  • ·Monitor kidney function during and after taper, especially in diabetic nephropathy patients

Warning Symptoms — Contact Your Doctor If You Experience:

  • Blood pressure rising above 140/90 mmHg
  • Headache or visual changes
  • Ankle swelling
  • Protein in urine increasing (diabetic patients)

Never change or stop a medication without consulting your prescribing physician.

Questions for Your Doctor

Questions to Ask

  • 1.Would lifestyle changes be enough without medication?
  • 2.Why losartan instead of lisinopril (or vice versa)?
  • 3.How often should my kidney function and potassium be checked?
  • 4.Could I try a lower dose first?

Lab Tests to Request

  • Blood pressure log (home monitoring)
  • Potassium levels
  • Kidney function (creatinine/BUN/GFR)
  • Urine protein (for diabetic nephropathy patients)

Medical Disclaimer

The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.

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