Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
COMBUNOX vs BIAXIN
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.
Binds to the 50S ribosomal subunit, inhibiting bacterial protein synthesis by blocking peptide chain elongation.
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.
Acute bacterial exacerbation of chronic bronchitis,Acute maxillary sinusitis,Community-acquired pneumonia,Pharyngitis/tonsillitis,Uncomplicated skin and skin structure infections,Helicobacter pylori eradication (as part of triple or dual therapy),Mycobacterium avium complex prophylaxis and treatment (off-label for some indications)
1 tablet (ibuprofen 400 mg/oxycodone HCl 10 mg) orally every 4 to 6 hours as needed for pain; maximum 4 tablets per day.
250-500 mg orally every 12 hours for 7-14 days; extended-release: 1000 mg orally every 24 hours for 7-14 days
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: 3-7 hours (single dose, 250-500 mg); with multiple dosing, half-life may extend to 7-10 hours due to saturable metabolism. Clinical context: Shorter half-life requires twice-daily dosing; extended half-life (via 14-hydroxy metabolite, t1/2 ~11 h) contributes to antibacterial activity.
Oxycodone: Primarily hepatic via CYP3A4 and CYP2D6 to active and inactive metabolites. Ibuprofen: Hepatic via CYP2C9 to inactive metabolites; also undergoes glucuronidation.
Primarily metabolized by CYP3A4 isoenzyme; clarithromycin undergoes first-pass metabolism to form 14-hydroxyclarithromycin (active metabolite).
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.
Approximately 20-30% of administered dose is excreted unchanged in urine; remainder is hepatically metabolized and excreted in bile and feces (~50% fecal elimination).
Oxycodone: ~45% bound primarily to albumin. Ibuprofen: >99% bound to albumin. No displacement interactions likely at therapeutic concentrations.
65-75% bound, primarily to albumin and alpha-1-acid glycoprotein.
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.
Vd: 2.6-3.5 L/kg. Clinical meaning: Large Vd indicates extensive tissue penetration, including lungs, tonsils, and sinuses, exceeding serum concentrations.
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 bioavailability: 50-55% (250 mg tablet); may be increased to 60-70% when administered with food. 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.
Cr Cl <30 m L/min: reduce dose by 50%; Cr Cl <10 m L/min: not recommended; no adjustment for Cr Cl >30 m L/min
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 Class C: reduce dose by 50% or consider alternative; mild to moderate hepatic impairment: no adjustment
Not approved for pediatric use; safety and efficacy not established in patients <18 years.
15 mg/kg/day orally divided every 12 hours; maximum 500 mg/day for 10 days; for extended-release, not recommended for children <12 years
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.
No specific dose adjustment; monitor renal function and adjust per renal guidelines; increased risk of QT prolongation
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.
None
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.
Increased risk of cardiac arrhythmias, including QT prolongation and torsades de pointes; avoid in patients with known QT prolongation or concurrent use with QT-prolonging drugs.,Potential for hepatotoxicity (elevated liver enzymes, hepatitis); monitor liver function.,Exacerbation of myasthenia gravis symptoms.,Clostridioides difficile-associated diarrhea (CDAD).,Drug interactions via CYP3A4 inhibition (e.g., statins, warfarin, colchicine, and other macrolides).,Pregnancy Category C; avoid use unless no alternative (clarithromycin associated with increased risk of miscarriage and fetal abnormalities in animal studies).
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 clarithromycin, erythromycin, or any macrolide antibiotic.,Concurrent use with pimozide, ergotamine, dihydroergotamine, lovastatin, simvastatin, or colchicine in renal/hepatic impairment.,History of cholestatic jaundice/hepatic dysfunction associated with prior clarithromycin use.,QT prolongation or history of ventricular arrhythmias (including torsades de pointes).,Concurrent use with antiarrhythmics (e.g., quinidine, procainamide, amiodarone) or other QT-prolonging drugs.,Severe hepatic failure or acute porphyria.
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.
Grapefruit and grapefruit juice should be avoided as they inhibit CYP3A4 and may increase clarithromycin levels, raising risk of QT prolongation. High-fat meals may delay absorption but do not significantly alter total exposure. Alcohol is not specifically contraindicated but may increase gastrointestinal irritation; avoid concurrent use of statins (especially simvastatin, lovastatin) due to increased myopathy risk.
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.
FDA Pregnancy Category C. Animal studies have shown fetal harm (cleft palate, skeletal abnormalities) at doses 2-5 times the human clinical dose. No adequate human studies. First trimester: Avoid unless benefit justifies risk. Second and third trimesters: Limited data; use only if clearly needed. Monitor for potential maternal hepatotoxicity.
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.
Clarithromycin is excreted into human breast milk; the milk-to-plasma ratio is approximately 0.25-0.5. Infants exposed via breast milk may experience gastrointestinal disturbances or altered gut flora. Use with caution, especially in infants younger than 6 weeks of age due to risk of hypertrophic pyloric stenosis. Consider temporary discontinuation during therapy if high doses are used.
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.
No specific pharmacokinetic studies have demonstrated a need for dose adjustment during pregnancy. However, pregnancy can increase volume of distribution and renal clearance; empirical dose monitoring is not required. Standard dosing regimens are applied unless hepatic or renal impairment is present.
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.
Biaxin (clarithromycin) is a macrolide antibiotic with activity against atypical pathogens (e.g., Legionella, Mycoplasma, Chlamydia). It is a potent CYP3A4 inhibitor, increasing levels of statins, warfarin, and colchicine. Use caution in myasthenia gravis; may exacerbate weakness. QT prolongation risk: avoid use with other QT-prolonging drugs, correct electrolyte abnormalities. For H. pylori eradication, combine with amoxicillin and a PPI as first-line. Renal dose adjustment required for Cr Cl <30 m L/min.
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.
Take with or without food, but taking with food may reduce stomach upset.,Complete the full course even if you feel better to prevent resistance.,Avoid grapefruit or grapefruit juice while on this medication.,Report any signs of liver problems: yellowing of skin/eyes, dark urine, severe nausea/vomiting.,May cause metallic or bitter taste in the mouth; this is usually temporary.,Tell your doctor if you have myasthenia gravis, as clarithromycin can worsen symptoms.,Avoid driving or operating heavy machinery if you experience dizziness or vision changes.,Use effective contraception if applicable; clarithromycin may reduce oral contraceptive efficacy.
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 BIAXIN, 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.. BIAXIN is a Macrolide Antibiotic that works by Binds to the 50S ribosomal subunit, inhibiting bacterial protein synthesis by blocking peptide chain elongation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between COMBUNOX and BIAXIN 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 BIAXIN is: 250-500 mg orally every 12 hours for 7-14 days; extended-release: 1000 mg orally every 24 hours for 7-14 days. 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 BIAXIN 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. BIAXIN is classified as Category C. FDA Pregnancy Category C. Animal studies have shown fetal harm (cleft palate, skeletal abnormalities) at doses 2-5 times the human clinical dose. No adequate human studies. First t. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.