Cozaar®
Losartan Potassium
Version 2025-04 · Last reviewed April 1, 2025 · Methodology
List Price
$40
With Insurance
$4-10
The Short Version
Evidence summary
Cozaar (Losartan Potassium) is a Angiotensin II Receptor Blocker (ARB) prescribed for Hypertension and Diabetic nephropathy. FDA-approved in 1995.
Blood pressure begins to fall within 3-6 hours. Peak blood levels of the active metabolite (EXP3174) occur within 3-4 hours.
The most commonly reported side effects are Upper respiratory infection (8%), Dizziness (3-4%), Back pain (2%). Reported in trials but may not be causally related
Most research was funded by the manufacturer — independent replication is limited.
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 loss — Approximately −1 mmHg systolic per kg lost.
The average American retiree spends $165,000 on healthcare over their lifetime (Fidelity, 2024). Informed choices today compound over decades.
Quick Answers
Now what?
You've read the evidence. Here are your next steps.
Related Evidence
Explore related medications reviewed on EvidentMeds
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.
Why the side effects happen
Because ARBs do not affect bradykinin (unlike ACE inhibitors), they rarely cause cough or angioedema. The main risks come from the intended mechanism: too much blood pressure lowering (dizziness) and too much angiotensin II blockade (hyperkalemia, kidney effects).
When Will I Feel It?
Blood pressure begins to fall within 3-6 hours. Peak blood levels of the active metabolite (EXP3174) occur within 3-4 hours.
Initial blood pressure lowering. Losartan is converted to its active metabolite (EXP3174) which is 10-40x more potent.
Maximum blood pressure reduction achieved. Allow at least 3 weeks before adjusting dose.
Sustained blood pressure control. Unlike ACE inhibitors, no cough development over time.
Adherence Note
Losartan has a relatively short half-life (6-9 hours for the active metabolite) compared to other ARBs. Some patients may need twice-daily dosing for 24-hour coverage.
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.
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.
Weight loss
Obesity drives hypertension through insulin resistance, sympathetic activation, and aldosterone excess. Weight loss addresses the root cause.
Approximately −1 mmHg systolic per kg lost
DASH diet pattern
High in vegetables, fruit, whole grains; low in ultra-processed food. Effective regardless of sodium intake level.
−8 to −14 mmHg systolic in hypertensive patients
Aerobic exercise
150 minutes/week of moderate activity. Lowers blood pressure through improved vascular function and reduced sympathetic tone.
−5 to −8 mmHg systolic
Alcohol reduction
Alcohol raises blood pressure dose-dependently. Reducing intake is one of the most underappreciated interventions.
−4 to −7 mmHg when reducing from moderate to low/none
Magnesium-rich foods
Leafy greens, nuts, seeds, dark chocolate. Magnesium promotes vascular relaxation and is depleted in many Western diets.
−4 to −5 mmHg in magnesium-deficient individuals
How It Compares
Losartan was the first ARB and remains the most prescribed. It is the go-to alternative for patients who develop cough on ACE inhibitors. Its unique uric acid-lowering effect may benefit patients with gout.
Strengths
- No ACE inhibitor cough (the #1 reason for switching)
- Very low angioedema risk
- Unique uric acid-lowering effect (may help gout patients)
- Cheap generic ($4)
- Well-tolerated overall
Weaknesses
- Shorter half-life than some other ARBs (may need twice-daily dosing)
- Active metabolite conversion depends on CYP2C9 — some people are poor metabolizers
- LIFE trial compared to atenolol (a weak comparator), limiting the strength of evidence
Clinically Preferred Alternatives
Global Prescribing & Pricing
Losartan is one of the most prescribed ARBs globally; widely used as a first-line antihypertensive
United States
$25-50/mo
Most prescribed ARB; often substituted for ACE inhibitors due to no cough
No lifestyle prerequisite
Usually covered
United Kingdom
~$2-5/mo
NICE alternative to ACE inhibitors when cough is an issue
Lifestyle advice required alongside prescribing
Fully covered by NHS
France
~$3-8/mo
First-line alternative to ACE inhibitors
Lifestyle counseling part of care pathway
Covered by Sécurité Sociale
Germany
~$4-10/mo
Widely prescribed first-line ARB
Lifestyle emphasis per DHL guidelines
Covered by GKV
Japan
~$15-30/mo
ARBs are preferred over ACE inhibitors in Japan — losartan widely used
Salt reduction programs widely promoted
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.
Funding Sources
LIFE: Funded by Merck & Co., the manufacturer of Cozaar (losartan). The trial compared losartan to atenolol and established the "ARB vs beta-blocker" narrative that drove billions in ARB prescriptions. RENAAL: Also funded by Merck. ELITE II: Also funded by Merck.
Declared Conflicts of Interest
All three pivotal trials were funded by Merck. Lead investigators had financial relationships with Merck. The LIFE trial specifically compared losartan to atenolol (a beta-blocker now considered inferior to other antihypertensives) — the choice of comparator flattered losartan's results.
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 carries a Cochrane RoB-2 risk-of-bias badge — tap the 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.
| Trial | Registry ID | Cite |
|---|---|---|
| LIFE (Merck) | NCT00338260 | |
| RENAAL (Merck) | NCT00308347 |
Bias ratings use Cochrane RoB-2 methodology. Editorial assessment — not a certified Cochrane review.
Our MethodologyMedical 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.
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)
Moderate Interactions (Caution)
Food Interactions
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.
Category D. Causes fetal kidney damage, oligohydramnios, and death in 2nd/3rd trimester. Discontinue immediately if pregnancy is detected.
Unknown if excreted in milk; potential for serious adverse effects in infant.
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 for hypertension in children 6+ with GFR >30.
No specific dose adjustment for age. Monitor renal function and potassium.
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
Community Reports
User-reported experiences — anonymous & anecdotal
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.
Stopping This Medication Safely
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.
Frequently Asked Questions About Cozaar®
- What is Cozaar® used for?
- Cozaar® (Losartan Potassium) is a Angiotensin II Receptor Blocker (ARB) manufactured by Generic (originally Merck). FDA-approved indications include: Hypertension; Diabetic nephropathy; Stroke prevention (in hypertension with LVH); Heart failure (when ACE inhibitors not tolerated).
- What are the common side effects of Cozaar®?
- Common side effects of Cozaar® include: Dizziness (3-4%); Upper respiratory infection (8%); Back pain (2%); Fatigue (2-4%); Diarrhea (2%).
- How much does Cozaar® cost?
- Cozaar® list price is approximately $40. With insurance it typically costs $4-10; without insurance approximately $10-25.
- Who funded the clinical trials for Cozaar®?
- LIFE: Funded by Merck & Co., the manufacturer of Cozaar (losartan). The trial compared losartan to atenolol and established the "ARB vs beta-blocker" narrative that drove billions in ARB prescriptions. RENAAL: Also funded by Merck. ELITE II: Also funded by Merck.
- How strong is the clinical evidence for Cozaar®?
- Key studies: LIFE, RENAAL, ELITE II. LIFE: 13% reduction in primary composite endpoint vs atenolol; 25% stroke reduction. RENAAL: 16% reduction in doubling of serum creatinine in diabetic nephropathy. Potential conflicts of interest: All three pivotal trials were funded by Merck. Lead investigators had financial relationships with Merck. The LIFE trial specifically compared losartan to atenolol (a beta-blocker now considered infer.
- Are there non-drug alternatives to Cozaar®?
- 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. See the Alternatives tab for full details.
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