Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ALEVE vs TYLENOL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Naproxen, a nonsteroidal anti-inflammatory drug (NSAID), inhibits cyclooxygenase (COX-1 and COX-2) enzymes, thereby reducing prostaglandin synthesis. This leads to decreased inflammation, pain, and fever.
Acetaminophen is a centrally acting analgesic and antipyretic. Its mechanism is not fully understood but involves inhibition of cyclooxygenase (COX) enzymes in the central nervous system, preferentially COX-2, and modulation of descending serotonergic pathways.
Rheumatoid arthritis,Osteoarthritis,Ankylosing spondylitis,Juvenile arthritis,Tendonitis,Bursitis,Acute gout,Primary dysmenorrhea,Mild to moderate pain,Fever
Mild to moderate pain (FDA-approved),Fever (FDA-approved),Osteoarthritis pain (off-label),Patent ductus arteriosus in neonates (off-label IV formulation)
220 mg orally every 8 to 12 hours as needed; maximum 660 mg per day.
650 mg orally every 4-6 hours or 1000 mg orally every 6 hours; maximum 4000 mg per day.
Terminal elimination half-life is 12-17 hours; allows twice-daily dosing for steady-state concentrations.
Terminal elimination half-life is 2-3 hours in adults; prolonged to 4-6 hours in neonates and patients with hepatic impairment
Naproxen is extensively metabolized in the liver primarily via CYP2C9 to 6-O-desmethyl naproxen, and less than 5% is excreted unchanged in urine.
Primarily hepatic via conjugation with glucuronide (UGT1A1, UGT1A6, UGT1A9) and sulfate (SULT1A1, SULT1A3); minor oxidation by CYP2E1, CYP1A2, and CYP3A4 to N-acetyl-p-benzoquinone imine (NAPQI), which is detoxified by glutathione.
Renal (95% as unchanged drug and metabolites); biliary/fecal (5%)
Renal excretion of conjugated metabolites (glucuronide and sulfate conjugates) accounts for >90% of elimination; less than 5% excreted unchanged; minor biliary/fecal elimination (<5%)
>99% bound to albumin; saturable at high concentrations.
10-25% bound to plasma proteins (primarily albumin); binding is minimal and not clinically significant
0.16 L/kg; indicates distribution primarily in extracellular fluid.
0.8-1.0 L/kg; low Vd indicates limited extravascular distribution, consistent with limited CNS penetration
Oral: ~95%; immediate-release formulation.
Oral: 60-90% (first-pass hepatic metabolism reduces bioavailability); Rectal: 70-90%; Intravenous: 100%
GFR 30-59 m L/min: reduce dose and avoid long-term use; GFR <30 m L/min: contraindicated.
GFR 10-50 m L/min: Administer every 6 hours. GFR <10 m L/min: Administer every 8 hours.
Child-Pugh class A: no adjustment; Child-Pugh class B or C: avoid use.
Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 50%; maximum 2000 mg/day. Child-Pugh C: Reduce dose by 75%; maximum 1000 mg/day.
2-12 years: 2.5-5 mg/kg/dose orally every 8-12 hours; maximum 10 mg/kg/day. 12 years and older: same as adult.
10-15 mg/kg orally every 4-6 hours; maximum 75 mg/kg/day or 5 doses per day.
Initiate at lowest effective dose (220 mg every 12 hours); maximum 440 mg per day; monitor renal function and GI bleeding risk.
Reduce dose by 25-50% in frail elderly; maximum 3000 mg/day due to increased hepatotoxicity risk.
Nonsteroidal anti-inflammatory drugs (NSAIDs) cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal. This risk may increase with duration of use. Patients with cardiovascular disease or risk factors may be at greater risk. Naproxen is contraindicated for treatment of peri-operative pain in the setting of coronary artery bypass graft (CABG) surgery. NSAIDs cause an increased risk of serious gastrointestinal adverse events including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal. These events can occur at any time during use and without warning symptoms. Elderly patients and patients with a prior history of peptic ulcer disease or GI bleeding are at greater risk.
Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen in doses exceeding 4000 mg per day. The risk of acute liver failure may be higher in individuals with underlying liver disease and in those who consume alcohol chronically.
Cardiovascular thrombotic events,Gastrointestinal bleeding, ulceration, and perforation,Hypertension,Heart failure and edema,Renal toxicity,Anaphylactoid reactions,Serious skin reactions (e.g., Stevens-Johnson syndrome),Hematologic toxicity (inhibition of platelet aggregation),Exacerbation of asthma,Hepatic effects,Pregnancy: avoid during third trimester
Hepatotoxicity: Risk increases with doses > 4000 mg/day, chronic alcohol use, or preexisting liver disease.,Severe skin reactions: Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis.,Hypersensitivity: Rare anaphylaxis.
History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs,Peri-operative pain in the setting of CABG surgery,Advanced renal disease,History of gastrointestinal bleeding or perforation related to previous NSAID therapy,Active gastrointestinal bleed
Hypersensitivity to acetaminophen,Severe hepatic impairment (e.g., active liver disease)
Avoid concurrent use of alcohol as it increases GI bleeding risk. No specific food restrictions; taking with food or milk may reduce dyspepsia. High potassium foods (e.g., bananas, spinach) may increase hyperkalemia risk in patients with renal impairment.
No significant food interactions. Alcohol consumption increases risk of hepatotoxicity; avoid concurrent use. High-carbohydrate meals may slightly delay absorption.
First trimester: Risk of spontaneous abortion and cardiac defects (odds ratio 1.86 for NSAIDs). Second trimester: Possible fetal renal dysfunction and oligohydramnios; ductus arteriosus premature closure risk begins. Third trimester: High risk of premature closure of ductus arteriosus, oligohydramnios, necrotizing enterocolitis, intracranial hemorrhage, and renal impairment; avoid after 30 weeks.
Acetaminophen crosses the placenta. First trimester: no increased risk of major malformations in prospective studies; retrospective studies show possible association with gastroschisis and neural tube defects but confounding by indication is likely. Second and third trimesters: no consistent evidence of adverse fetal effects; chronic high doses may cause maternal hepatotoxicity with secondary fetal effects. Avoid prolonged high-dose therapy.
Excreted in breast milk in low concentrations (M/P ratio ~0.12); relative infant dose <1% of maternal weight-adjusted dose. Compatible with breastfeeding; monitor infant for potential adverse effects (gastrointestinal upset, rash) at higher doses.
Acetaminophen is excreted into breast milk in low amounts (M/P ratio approximately 0.9; peak milk concentration 10-15 µg/m L after 1g oral dose). Relative infant dose is <2% of maternal weight-adjusted dose. Considered compatible with breastfeeding; monitor infant for rash or drowsiness.
No specific pharmacokinetic-based dose adjustments; however, use lowest effective dose for shortest duration, especially after 20 weeks. Avoid use after 30 weeks gestation due to fetal risks. Increased volume of distribution may reduce serum concentrations but no dose adjustment recommended.
Increased clearance in pregnancy may reduce AUC by 25-30%; recommend standard dosing (500-1000mg every 4-6 hours, max 3000-4000mg/day). No dosage adjustment typically needed. Avoid extended-release formulations due to variable absorption.
ALEVE (naproxen sodium) is a nonsteroidal anti-inflammatory drug (NSAID) with a longer half-life (12-17 hours) allowing twice-daily dosing. It carries a boxed warning for cardiovascular and gastrointestinal risk. Use lowest effective dose for shortest duration. Contraindicated in patients with aspirin allergy, perioperative pain in CABG surgery, and significant renal impairment. Monitor renal function in elderly, volume-depleted patients, and those on ACE inhibitors or diuretics.
Acetaminophen has minimal anti-inflammatory effect; prefer NSAIDs for inflammation. Max daily dose 3 g (or 2 g in at-risk patients). N-acetylcysteine is antidote for overdose; administer if serum level above nomogram line. Avoid in severe hepatic impairment. Intravenous formulation available for acute pain. Onset of action 30-60 min, duration 4-6 h. No effect on platelets or GI mucosa.
Take with food or milk to reduce GI upset.,Do not exceed 2 tablets (440 mg) in 24 hours unless directed by a doctor.,Avoid alcohol consumption to lower risk of GI bleeding.,Stop use and seek medical help if you experience chest pain, weakness, slurred speech, or signs of stomach bleeding (black/tarry stools, vomit that looks like coffee grounds).,Do not use with other NSAIDs (e.g., ibuprofen, aspirin) unless prescribed.
Do not exceed 3 g (3000 mg) per day from all products.,Check all over-the-counter medications for acetaminophen content.,Do not take with alcohol or if you have liver disease.,Seek immediate medical attention if overdose is suspected.,May be taken with food if GI upset occurs (though rare).
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ALEVE vs TYLENOL, answered by our medical review team.
ALEVE is a Nonsteroidal Anti-inflammatory Drug (NSAID) that works by Naproxen, a nonsteroidal anti-inflammatory drug (NSAID), inhibits cyclooxygenase (COX-1 and COX-2) enzymes, thereby reducing prostaglandin synthesis. This leads to decreased inflammation, pain, and fever.. TYLENOL is a Analgesic (non-opioid) that works by Acetaminophen is a centrally acting analgesic and antipyretic. Its mechanism is not fully understood but involves inhibition of cyclooxygenase (COX) enzymes in the central nervous system, preferentially COX-2, and modulation of descending serotonergic pathways.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ALEVE and TYLENOL depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ALEVE is: 220 mg orally every 8 to 12 hours as needed; maximum 660 mg per day.. The standard adult dose of TYLENOL is: 650 mg orally every 4-6 hours or 1000 mg orally every 6 hours; maximum 4000 mg per day.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ALEVE and TYLENOL in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ALEVE is classified as Category C. First trimester: Risk of spontaneous abortion and cardiac defects (odds ratio 1.86 for NSAIDs). Second trimester: Possible fetal renal dysfunction and oligohydramnios; ductus arter. TYLENOL is classified as Category C. Acetaminophen crosses the placenta. First trimester: no increased risk of major malformations in prospective studies; retrospective studies show possible association with gastrosch. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.