Drug Comparison

Losartan Potassium vs. Naproxen

Compare Losartan Potassium and Naproxen: mechanism of action, indications, side effects, cost, and which may be right for you.

Quick Comparison

CategoryLosartan PotassiumNaproxen
Drug ClassARBs (Angiotensin II Receptor Blockers)NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)
Rx StatusRxRx
Generic AvailableNoNo
Typical Cost$4–$15/month$4–$25/month

Losartan Potassium Overview

Losartan potassium (Cozaar) is an angiotensin II receptor blocker (ARB) used to treat high blood pressure, protect the kidneys in type 2 diabetes, and reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy. Unlike ACE inhibitors, losartan does not cause a dry cough and carries a significantly lower risk of angioedema. It is also the only ARB with a clinically mean...

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Naproxen Overview

NAPROXEN (brand name: Naproxen) is a NSAIDs. 1 INDICATIONS & USAGE Naproxen delayed-release tablets are indicated for: the relief of the signs and symptoms of: rheumatoid arthritis osteoarthritis ankylosing spondylitis Polyarticular Juvenile Idiopathic Arthritis Naproxen delayed-release tablets are non-steroidal anti-inflammatory drugs…

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How Each Drug Works

Losartan Potassium

Mechanism of Action — AT1 Receptor Blockade

Losartan is a selective, competitive antagonist of the angiotensin II type 1 (AT1) receptor. Unlike ACE inhibitors, losartan does not prevent the formation of angiotensin II — instead, it blocks angiotensin II from binding to its primary receptor.

Step-by-step mechanism:

  1. Renin-angiotensin-aldosterone system (RAAS) activation: Renin converts angiotensinogen to angiotensin I; ACE converts angiotensin I to angiotensin II via multiple pat…

Naproxen

Naproxen has analgesic, anti-inflammatory, and antipyretic properties. The mechanism of action of naproxen, like that of other NSAIDs, is not completely understood but involves inhibition of cyclooxygenase (COX-1 and COX-2). Naproxen is a potent inhibitor of prostaglandin synthesis in vitro. Naproxen concentrations reached during therapy have produced in vivo effects. Prostaglandins sensitize afferent nerves and potentiate the action of bradykinin in inducing pain in ani…

Approved Uses (Indications)

Losartan Potassium

FDA-Approved Indications:

Hypertension (adults and pediatric patients ≥6 years):

  • Treatment of hypertension to reduce blood pressure and lower the risk of cardiovascular events
  • Can be used as monotherapy or in combination with other antihypertensives
  • Pediatric use: approved for children ≥6 years with eGFR >30 mL/min/1.73m²

Diabetic Nephropathy (type 2 diabetes with proteinuria and hypertension):

  • Reduces the rate of progression of nephropathy as measured by doubling of serum creatinine or ESRD
  • RENAAL trial: 25% reduction in doubling of serum creatinine, 28% reduction in E…

Naproxen

Naproxen delayed-release tablets are indicated for: the relief of the signs and symptoms of: rheumatoid arthritis osteoarthritis ankylosing spondylitis Polyarticular Juvenile Idiopathic Arthritis Naproxen delayed-release tablets are non-steroidal anti-inflammatory drugs indicated for: the relief of the signs and symptoms of: rheumatoid arthritis osteoarthritis ankylosing spondylitis polyarticular juvenile idiopathic arthritis

Side Effects

Losartan Potassium

Serious Side Effects

Hyperkalemia — can be severe (>6 mEq/L) in patients with renal impairment, diabetes, or concurrent use of potassium-sparing agentsAcute kidney injury — especially in patients with bilateral renal artery stenosis, solitary kidney, or severe heart failureHypotension — particularly in volume-depleted patients (diuretics, low-sodium diet, dialysis); first-dose effectAngioedema — rare (<0.1%), but can occur; 3–4× less common than with ACE inhibitors; may occur in patients with prior ACE inhibitor-induced angioedemaFetal/neonatal toxicity — can cause oligohydramnios, fetal renal dysfunction, skull hypoplasia, and death (Category D in 2nd/3rd trimester)

Common Side Effects

Dizziness (4–7%)Upper respiratory infection (8%)Fatigue (3–4%)Hyperkalemia (potassium >5.5 mEq/L, especially with renal impairment or diabetes)Hypotension (especially in volume-depleted patients)Elevated serum creatinine (reversible, especially with bilateral renal artery stenosis)Back pain (2–3%)Nasal congestion (2%)

Rare Side Effects

Hepatotoxicity (rare case reports)Rhabdomyolysis (rare, especially with concurrent statin use)Anemia (rare, especially in patients with renal impairment)Thrombocytopenia (rare)

Naproxen

Cost Comparison

Losartan Potassium

$4–$15/month

Generic losartan potassium is available at most pharmacies for $4–$15/month, and is included on most $4 generic drug programs at major pharmacy chains (Walmart, Kroger, Costco). Brand-name Cozaar is significantly more expensive (~$200–$300/month) but is rarely prescribed. Hyzaar (losartan/hydrochlorothiazide combination) is also available generically at similar low cost. GoodRx and RxGo coupons can further reduce the price at most pharmacies.

Naproxen

$4–$25/month

Naproxen is widely available as an affordable generic. Using discount cards like GoodRx can further reduce the cost, often bringing it to under $10 per month.

Drug Interaction: Moderate

Naproxen, like all NSAIDs, can reduce the antihypertensive effect of losartan and increase the risk of acute kidney injury. The mechanism and clinical significance are identical to the losartan-ibuprofen interaction. Naproxen has a longer half-life (12–17 hours) than ibuprofen, which may prolong the duration of the interaction.

Mechanism: Naproxen inhibits COX-1 and COX-2, reducing prostaglandin-mediated renal vasodilation and causing sodium/water retention. This directly opposes the antihypertensive and renal-protective effects of losartan. In patients with reduced renal reserve, the combination can precipitate acute kidney injury through the same 'triple whammy' mechanism as ibuprofen.

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Medical Disclaimer

The information on RxGuide is intended for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician, pharmacist, or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.