Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
BONTRIL vs ALEVE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Bontril (phendimetrazine) is a sympathomimetic amine that acts as an appetite suppressant. Its mechanism involves stimulating the hypothalamus to release norepinephrine and dopamine, which reduces hunger cues. It is a prodrug that is metabolized to the active agent phenmetrazine, which inhibits reuptake and increases release of norepinephrine and dopamine in the central nervous system.
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.
FDA-approved for management of obesity as a short-term adjunct (few weeks) in a regimen of weight reduction based on caloric restriction, exercise, and behavior modification. Off-label uses are not well documented due to limited evidence.
Rheumatoid arthritis,Osteoarthritis,Ankylosing spondylitis,Juvenile arthritis,Tendonitis,Bursitis,Acute gout,Primary dysmenorrhea,Mild to moderate pain,Fever
BONTRIL 50 mg orally once daily, with or without food.
220 mg orally every 8 to 12 hours as needed; maximum 660 mg per day.
18-24 hours; prolonged in renal impairment (up to 40 hours) requiring dose adjustment.
Terminal elimination half-life is 12-17 hours; allows twice-daily dosing for steady-state concentrations.
Phendimetrazine is extensively metabolized in the liver, primarily via N-demethylation to its active metabolite phenmetrazine. Minor pathways include hydroxylation and conjugation. Cytochrome P450 enzymes are involved, though specific isoforms are not fully characterized.
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 renal (60-70% unchanged) with minor biliary/fecal (10-15% as metabolites).
Renal (95% as unchanged drug and metabolites); biliary/fecal (5%)
85-90% bound to albumin and alpha-1-acid glycoprotein.
>99% bound to albumin; saturable at high concentrations.
3-5 L/kg; indicates extensive tissue distribution.
0.16 L/kg; indicates distribution primarily in extracellular fluid.
Oral: 70-80% (first-pass metabolism); IV: 100%.
Oral: ~95%; immediate-release formulation.
GFR >60 m L/min: no adjustment. GFR 30-60 m L/min: reduce dose to 25 mg once daily. GFR <30 m L/min: use is not recommended.
GFR 30-59 m L/min: reduce dose and avoid long-term use; GFR <30 m L/min: contraindicated.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose to 25 mg once daily. Child-Pugh Class C: use is contraindicated.
Child-Pugh class A: no adjustment; Child-Pugh class B or C: avoid use.
Weight-based: 1 mg/kg orally once daily, with a maximum of 50 mg. Not recommended for children weighing less than 10 kg.
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.
Start at 25 mg orally once daily; may increase to 50 mg after 2 weeks if tolerated and renal function is adequate (Cr Cl >60 m L/min).
Initiate at lowest effective dose (220 mg every 12 hours); maximum 440 mg per day; monitor renal function and GI bleeding risk.
None
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.
Risk of abuse, dependence, and tolerance; monitor for signs of addiction.,May cause serious cardiovascular events including pulmonary hypertension and valvular heart disease, especially with long-term use.,May impair ability to drive or operate machinery due to dizziness or blurred vision.,Use with caution in patients with hypertension, hyperthyroidism, glaucoma, or history of drug abuse.,Concomitant use with other sympathomimetics or MAO inhibitors can cause hypertensive crisis.,Not recommended for use in patients with a history of epilepsy or those taking other anorectic agents.
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
Known hypersensitivity to phendimetrazine or any component of the formulation.,History of cardiovascular disease including coronary artery disease, arrhythmias, or congestive heart failure.,Hypertension (moderate to severe).,Hyperthyroidism.,Glaucoma.,History of drug abuse or alcoholism.,Concurrent use of monoamine oxidase inhibitors or within 14 days of such use.,Pregnancy and breastfeeding.,Agitated states.,History of seizure disorders.
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
Avoid high-fat meals as they may delay absorption of oral formulations. No specific food-drug interactions known; however, anticholinergic effects may be exacerbated by alcohol.
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.
BONTRIL is classified as FDA Pregnancy Category X. First trimester: high risk of major congenital malformations including neural tube defects, cardiovascular anomalies, and cleft palate. Second and third trimesters: risk of fetal growth restriction, oligohydramnios, and neonatal respiratory depression if used near term.
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.
No data available on excretion into human breast milk. M/P ratio unknown. Due to potential for serious adverse effects in nursing infants, breastfeeding is contraindicated during BONTRIL 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.
No dose adjustment required for pregnancy. However, due to teratogenicity, BONTRIL should be discontinued before conception or as soon as pregnancy is diagnosed.
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.
BONTRIL (hyoscyamine) is an anticholinergic used for GI spasms; avoid in patients with glaucoma, myasthenia gravis, or obstructive uropathy. Onset of action is 2-3 minutes IV; monitor for heat stroke in high ambient temperatures due to decreased sweating.
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.
Do not drive or operate machinery until you know how this medication affects you, as it may cause dizziness or blurred vision.,Avoid alcohol and other CNS depressants as they may increase sedation.,Report immediately if you experience eye pain, difficulty urinating, or rapid heartbeat.,Use caution in hot weather; this drug reduces sweating and increases risk of heat stroke.
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.
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 BONTRIL vs ALEVE, answered by our medical review team.
BONTRIL is a Sympathomimetic Anorectic that works by Bontril (phendimetrazine) is a sympathomimetic amine that acts as an appetite suppressant. Its mechanism involves stimulating the hypothalamus to release norepinephrine and dopamine, which reduces hunger cues. It is a prodrug that is metabolized to the active agent phenmetrazine, which inhibits reuptake and increases release of norepinephrine and dopamine in the central nervous system.. 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.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between BONTRIL and ALEVE 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 BONTRIL is: BONTRIL 50 mg orally once daily, with or without food.. The standard adult dose of ALEVE is: 220 mg orally every 8 to 12 hours as needed; maximum 660 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 BONTRIL and ALEVE 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. BONTRIL is classified as Category C. BONTRIL is classified as FDA Pregnancy Category X. First trimester: high risk of major congenital malformations including neural tube defects, cardiovascular anomalies, and cleft p. 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. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.