Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
COMBUNOX vs TYLENOL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
COMBUNOX is a fixed-dose combination of oxycodone, a full mu-opioid receptor agonist, and ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2), thereby reducing prostaglandin synthesis.
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.
FDA-approved: Short-term (up to 7 days) management of acute pain severe enough to require an opioid analgesic and for which alternative treatments are inadequate.,Off-label: None commonly recognized.
Mild to moderate pain (FDA-approved),Fever (FDA-approved),Osteoarthritis pain (off-label),Patent ductus arteriosus in neonates (off-label IV formulation)
1 tablet (ibuprofen 400 mg/oxycodone HCl 10 mg) orally every 4 to 6 hours as needed for pain; maximum 4 tablets per day.
650 mg orally every 4-6 hours or 1000 mg orally every 6 hours; maximum 4000 mg per day.
Oxycodone terminal half-life is 3.5-5.5 hours (mean ~3.8 hours) in immediate-release form; controlled-release formulations have a prolonged absorption phase with an effective half-life of 4.5-8 hours. Ibuprofen terminal half-life is 1.8-2.5 hours (mean ~2 hours). Clinical context: Oxycodone's half-life supports dosing every 4-6 hours (IR) or 12 hours (CR); ibuprofen's short half-life requires frequent dosing for sustained anti-inflammatory effect. In elderly or hepatic impairment, oxycodone half-life may increase to 6-8 hours; ibuprofen half-life may be slightly prolonged.
Terminal elimination half-life is 2-3 hours in adults; prolonged to 4-6 hours in neonates and patients with hepatic impairment
Oxycodone: Primarily hepatic via CYP3A4 and CYP2D6 to active and inactive metabolites. Ibuprofen: Hepatic via CYP2C9 to inactive metabolites; also undergoes glucuronidation.
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.
Oxycodone is primarily metabolized in the liver; metabolites are excreted mainly in urine. Approximately 87% of an oral dose is eliminated within 24 hours: 60-70% as oxycodone metabolites (mostly noroxycodone and oxymorphone conjugates) and 10-15% as unchanged oxycodone. Ibuprofen is rapidly metabolized and excreted; about 90% of a dose is eliminated in urine as metabolites (primarily hydroxylated and carboxylated forms) and <1% as unchanged drug. Biliary/fecal elimination accounts for <10% of each component.
Renal excretion of conjugated metabolites (glucuronide and sulfate conjugates) accounts for >90% of elimination; less than 5% excreted unchanged; minor biliary/fecal elimination (<5%)
Oxycodone: ~45% bound primarily to albumin. Ibuprofen: >99% bound to albumin. No displacement interactions likely at therapeutic concentrations.
10-25% bound to plasma proteins (primarily albumin); binding is minimal and not clinically significant
Oxycodone: Vd of 2.0-3.0 L/kg (mean ~2.6 L/kg), indicating extensive tissue distribution. Ibuprofen: Vd of 0.1-0.2 L/kg (mean ~0.15 L/kg), confined to plasma and extracellular fluid. Combined formulation Vd not significantly altered.
0.8-1.0 L/kg; low Vd indicates limited extravascular distribution, consistent with limited CNS penetration
Oral bioavailability of oxycodone: 60-87% (mean ~75%) with first-pass metabolism accounting for ~25% loss. Ibuprofen: >80% (mean ~95%) with minimal first-pass effect. Food reduces rate but not extent of absorption; taking with food may delay peak concentrations by 1-2 hours.
Oral: 60-90% (first-pass hepatic metabolism reduces bioavailability); Rectal: 70-90%; Intravenous: 100%
GFR 30-89 m L/min: No adjustment needed. GFR <30 m L/min: Avoid use due to ibuprofen component. Hemodialysis: Not recommended.
GFR 10-50 m L/min: Administer every 6 hours. GFR <10 m L/min: Administer every 8 hours.
Child-Pugh A: No adjustment. Child-Pugh B: Reduce oxycodone dose by 50% (e.g., consider alternative). Child-Pugh C: Avoid use (contraindicated).
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.
Not approved for pediatric use; safety and efficacy not established in patients <18 years.
10-15 mg/kg orally every 4-6 hours; maximum 75 mg/kg/day or 5 doses per day.
Initiate at lower dose (e.g., 1 tablet of ibuprofen 200 mg/oxycodone HCl 5 mg) every 6 hours as needed; monitor for CNS depression and renal function. Maximum 4 tablets per day.
Reduce dose by 25-50% in frail elderly; maximum 3000 mg/day due to increased hepatotoxicity risk.
Addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; risk of serious cardiovascular and gastrointestinal events with NSAIDs.
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.
Respiratory depression; addiction potential; CNS depression; hepatotoxicity; renal toxicity; gastrointestinal bleeding; cardiovascular thrombotic events; anaphylactic reactions; drug interactions with CYP3A4 inhibitors/inducers; avoid in severe hepatic impairment.
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.
Significant respiratory depression; acute or severe bronchial asthma; paralytic ileus; known hypersensitivity to oxycodone, ibuprofen, or any component; patients with gastrointestinal bleeding or perforation; advanced renal disease; coronary artery bypass graft (CABG) surgery perioperative pain; use of MAO inhibitors within 14 days.
Hypersensitivity to acetaminophen,Severe hepatic impairment (e.g., active liver disease)
Avoid alcohol. Taking with food decreases GI irritation. Grapefruit juice may increase oxycodone levels; limit intake. High-fat meals can delay but not reduce oxycodone absorption.
No significant food interactions. Alcohol consumption increases risk of hepatotoxicity; avoid concurrent use. High-carbohydrate meals may slightly delay absorption.
COMBUNOX (oxycodone/ibuprofen) is pregnancy category C prior to 30 weeks and category D after 30 weeks. First trimester: limited data, potential neural tube defects with NSAIDs; second trimester: NSAID use associated with fetal renal dysfunction and oligohydramnios; third trimester: NSAIDs may cause premature closure of ductus arteriosus, pulmonary hypertension, and oligohydramnios; oxycodone may lead to neonatal opioid withdrawal syndrome (NOWS) with chronic use.
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.
Oxycodone excreted in breast milk; M/P ratio approximately 3.6:1. Ibuprofen minimal transfer (M/P ~0.01). Relative infant dose (RID) for oxycodone ~3.5% of maternal weight-adjusted dose; ibuprofen <0.1%. Potential for infant sedation, respiratory depression, and withdrawal. Use caution; avoid if mother is a CYP2D6 ultra-rapid metabolizer. American Academy of Pediatrics recommends use with monitoring.
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 dose adjustment for pregnancy is established. However, increased renal clearance in pregnancy may reduce ibuprofen levels; clinical significance unknown. Oxycodone pharmacokinetics altered: increased volume of distribution and clearance may require higher doses for analgesia. Use lowest effective dose and shortest duration. Avoid prolonged use >48 hours near term due to risk of premature ductus closure.
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.
Combunox contains ibuprofen 400 mg and oxycodone 5 mg. The fixed-dose combination limits flexibility; use only when both components are needed. Monitor for GI bleeding, renal impairment, and opioid-related respiratory depression. Avoid in patients with severe asthma, NSAID allergy, or opioid intolerance. Watch for drug interactions with anticoagulants, SSRIs, and CYP3A4 inhibitors/inducers. The combination increases risk of serotonin syndrome if used with other serotonergic drugs.
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 stomach upset.,Do not exceed prescribed dose; can cause liver damage, stomach bleeding, or addiction.,Avoid alcohol while taking this medication.,May cause dizziness or drowsiness; do not drive until you know how it affects you.,Report sudden stomach pain, black stool, or vomiting blood.,Stop use and seek emergency care if signs of allergic reaction (rash, difficulty breathing) occur.,Do not combine with other NSAIDs or acetaminophen without consulting provider.,Store securely to prevent accidental overdose or misuse.
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 COMBUNOX vs TYLENOL, answered by our medical review team.
COMBUNOX is a Analgesic Combination (Opioid + NSAID) that works by COMBUNOX is a fixed-dose combination of oxycodone, a full mu-opioid receptor agonist, and ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2), thereby reducing prostaglandin synthesis.. 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 COMBUNOX 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 COMBUNOX is: 1 tablet (ibuprofen 400 mg/oxycodone HCl 10 mg) orally every 4 to 6 hours as needed for pain; maximum 4 tablets 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 COMBUNOX 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. COMBUNOX is classified as Category C. COMBUNOX (oxycodone/ibuprofen) is pregnancy category C prior to 30 weeks and category D after 30 weeks. First trimester: limited data, potential neural tube defects with NSAIDs; se. 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.