Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
COMBOGESIC vs DAYPRO
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
COMBOGESIC (acetaminophen and tramadol) combines a centrally acting analgesic (tramadol) that binds to mu-opioid receptors and inhibits serotonin and norepinephrine reuptake, with an antipyretic (acetaminophen) that inhibits cyclooxygenase (COX) in the CNS.
Nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), reducing prostaglandin synthesis and thereby alleviating pain and inflammation.
Management of acute pain severe enough to require an opioid analgesic and for which alternative treatments are inadequate in adults
Osteoarthritis,Rheumatoid arthritis
One tablet (acetaminophen 500 mg / tramadol 37.5 mg) orally every 4 to 6 hours as needed for pain, not to exceed 8 tablets per day.
600 mg orally once daily; max 1200 mg/day
Acetaminophen: 2-3 hours; Tramadol: 6.3 hours (slow CYP2D6 metabolizers may exceed 12 hours). Clinically, dosing interval adjusted for renal impairment.
Approximately 40-70 hours (mean ~50 h), allowing once-daily dosing; steady-state reached in 4-6 days.
Tramadol: primarily metabolized by CYP2D6 and CYP3A4; O-desmethyltramadol (active metabolite) via CYP2D6. Acetaminophen: primarily metabolized by glucuronidation and sulfation in the liver.
Primarily hepatic via CYP2C9; undergoes glucuronidation.
Renal excretion of acetaminophen metabolites (glucuronide, sulfate, cysteine, and mercapturate conjugates); 85% total. Tramadol and metabolites: 90% renal, 10% fecal.
Renal (approx. 70-80% as unchanged drug and glucuronide conjugate; biliary/fecal excretion accounts for the remainder).
Acetaminophen 10-25%; Tramadol 20% bound to albumin.
>99% bound primarily to albumin.
Acetaminophen 0.9 L/kg; Tramadol 2.6 L/kg. Reflects extensive tissue distribution.
0.15-0.2 L/kg; indicates limited extravascular distribution mainly in plasma and extracellular fluid.
Acetaminophen oral ~88%; Tramadol oral ~75% (due to first-pass metabolism).
Oral: approximately 80-90%.
For Cr Cl 30-59 m L/min: increase dosing interval to every 12 hours, maximum 4 tablets per day. For Cr Cl <30 m L/min: not recommended. Hemodialysis: administer dose after dialysis session, use with caution.
Cr Cl 30-59 m L/min: 600 mg once daily; Cr Cl <30 m L/min: 400 mg once daily; hemodialysis: 400 mg once daily after dialysis
Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% or extend interval; maximum 4 tablets per day. Child-Pugh Class C: contraindicated.
Child-Pugh Class A: no adjustment; Class B: 400 mg once daily; Class C: avoid use
Not recommended for pediatric use. Safety and efficacy not established in children.
Not approved for pediatric use
Initiate at lowest effective dose; consider extended dosing interval (every 8-12 hours) and monitor for adverse effects, particularly CNS and respiratory depression.
Initiate at 400 mg once daily; max 600 mg once daily; monitor renal function
Risk of addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risk of medication errors (combining different forms of acetaminophen leading to hepatotoxicity); serious, life-threatening, or fatal respiratory depression may occur when used with benzodiazepines or other CNS depressants.
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 occur early in treatment and may increase with duration of use. DAYPRO is contraindicated in the setting of coronary artery bypass graft (CABG) surgery.
Addiction, abuse, and misuse; life-threatening respiratory depression; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; hepatotoxicity (associated with acetaminophen); seizures; serotonin syndrome; risk of overdose; interactions with MAOIs; CYP2D6 poor metabolizers may have reduced efficacy; risk of anaphylaxis and hypersensitivity.
Cardiovascular risk, gastrointestinal bleeding and ulceration, renal toxicity, hypertension, anaphylactoid reactions, serious skin reactions, hematologic toxicity (anemia), hepatic effects, asthma exacerbation, fluid retention, and use in pregnancy (avoid in late pregnancy).
Hypersensitivity to tramadol, acetaminophen, or any component; significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or without resuscitative equipment; known or suspected gastrointestinal obstruction, including paralytic ileus; concomitant use of MAOIs or within 14 days of such therapy.
Aspirin allergy, history of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs, perioperative pain in the setting of CABG surgery, advanced renal disease, and pregnancy (third trimester).
Avoid alcohol while taking Combogesic, as it increases the risk of liver damage with acetaminophen and gastrointestinal bleeding with ibuprofen. Taking with food may reduce gastric irritation. No specific food restrictions.
No significant food interactions. However, taking with food or antacids can reduce GI irritation. Avoid alcohol to minimize risk of gastric mucosal injury.
Combogesic contains paracetamol (acetaminophen) and tramadol. Paracetamol: No increased risk of major malformations; first trimester use is generally considered low risk. Second and third trimester: No known fetal toxicity at therapeutic doses. Tramadol: First trimester: Limited data, but no major teratogenicity observed in animal studies; human data insufficient to exclude risk. Second and third trimester: Not associated with structural anomalies; chronic use may lead to fetal dependence and neonatal withdrawal syndrome. At term: Risk of neonatal respiratory depression if used near delivery; tramadol may prolong labor and increase risk of postpartum hemorrhage.
Daypro (oxaprozin) is a nonsteroidal anti-inflammatory drug (NSAID) with teratogenic potential. First trimester: Avoid; associated with increased risk of miscarriage and cardiac defects. Second trimester: Use only if clearly needed; possible oligohydramnios and fetal renal impairment. Third trimester: Contraindicated due to risk of premature closure of ductus arteriosus, oligohydramnios, and neonatal pulmonary hypertension.
Paracetamol: Excreted into breast milk in small amounts (M/P ratio ~0.23-0.91); considered compatible with breastfeeding. Tramadol: Excreted into breast milk (M/P ratio ~1.5-2.0); relative infant dose ~2.24% of maternal weight-adjusted dose. Monitor infant for sedation and respiratory depression; avoid in women with CYP2D6 ultra-rapid metabolizer status due to increased risk of high morphine levels in breast milk.
Oxaprozin is excreted into breast milk in low concentrations (M/P ratio approximately 0.1-0.3). Due to potential adverse effects on infant renal function and platelet function, caution is advised. Avoid long-term use; short-term use with infant monitoring recommended.
Paracetamol: No adjustment required; use lowest effective dose for shortest duration. Tramadol: Pregnancy may alter tramadol pharmacokinetics (increased clearance, decreased Cmax); however, no standard dose adjustment is recommended. Use minimal effective dose; avoid sustained-release formulations. Near term: Consider alternative analgesics to minimize neonatal effects.
No specific dose adjustments established; however, pharmacokinetic changes in pregnancy (increased volume of distribution, altered hepatic metabolism) may require dose titration based on clinical response. Use lowest effective dose for shortest duration. Avoid in third trimester.
Combogesic (paracetamol/acetaminophen + ibuprofen) is a fixed-dose combination used for acute pain. Note that the maximum daily dose of acetaminophen is 4000 mg (or lower in hepatic impairment) and ibuprofen 1200 mg (or lower in renal impairment). Avoid concomitant use of other NSAIDs or acetaminophen-containing products. Use with caution in patients with a history of peptic ulcer or bleeding disorders; ibuprofen may increase bleeding risk.
Daypro (oxaprozin) is a nonsteroidal anti-inflammatory drug (NSAID) with a long half-life (~50-60 hours) allowing once-daily dosing. Use with caution in elderly or renal impairment due to reduced clearance. Monitor renal function, hepatic enzymes, and signs of GI bleeding. Avoid use with other NSAIDs or aspirin. May increase lithium, methotrexate, and warfarin levels.
Do not exceed the recommended dose as it may cause liver damage or kidney problems.,Avoid taking other products containing acetaminophen or NSAIDs (e.g., ibuprofen, naproxen) while using Combogesic.,Take with food or milk to reduce stomach upset.,Report any signs of stomach bleeding (e.g., black/tarry stools, vomiting blood), rash, or swelling.,Do not use for more than 10 days for pain unless directed by a doctor.
Take with food or milk to reduce stomach upset.,Swallow tablets whole; do not crush or chew.,Avoid alcohol while taking this medication.,Report signs of bleeding (black/tarry stools, unusual bruising), weight gain, or edema.,Do not take with other NSAIDs or over-the-counter pain relievers without consulting your doctor.
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 COMBOGESIC vs DAYPRO, answered by our medical review team.
COMBOGESIC is a Analgesic Combination (Opioid + Non-Opioid) that works by COMBOGESIC (acetaminophen and tramadol) combines a centrally acting analgesic (tramadol) that binds to mu-opioid receptors and inhibits serotonin and norepinephrine reuptake, with an antipyretic (acetaminophen) that inhibits cyclooxygenase (COX) in the CNS.. DAYPRO is a Nonsteroidal Anti-Inflammatory Drug (NSAID) that works by Nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), reducing prostaglandin synthesis and thereby alleviating pain and inflammation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between COMBOGESIC and DAYPRO 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 COMBOGESIC is: One tablet (acetaminophen 500 mg / tramadol 37.5 mg) orally every 4 to 6 hours as needed for pain, not to exceed 8 tablets per day.. The standard adult dose of DAYPRO is: 600 mg orally once daily; max 1200 mg/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 COMBOGESIC and DAYPRO 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. COMBOGESIC is classified as Category C. Combogesic contains paracetamol (acetaminophen) and tramadol. Paracetamol: No increased risk of major malformations; first trimester use is generally considered low risk. Second an. DAYPRO is classified as Category C. Daypro (oxaprozin) is a nonsteroidal anti-inflammatory drug (NSAID) with teratogenic potential. First trimester: Avoid; associated with increased risk of miscarriage and cardiac de. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.