Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ROXIPRIN vs ANEXSIA 7.5/325
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Roxiprin is a combination analgesic containing rofecoxib (a COX-2 selective NSAID) and paracetamol (acetaminophen, a centrally acting analgesic/antipyretic). Rofecoxib inhibits prostaglandin synthesis by selectively blocking cyclooxygenase-2, reducing pain and inflammation. Paracetamol inhibits cyclooxygenase in the central nervous system and modulates descending serotonergic pathways, providing analgesia and antipyresis.
Hydrocodone is a mu-opioid receptor agonist, producing analgesia and euphoria. Acetaminophen inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis and providing analgesic and antipyretic effects.
Relief of mild to moderate pain,Fever reduction,Management of osteoarthritis and rheumatoid arthritis (rofecoxib component)
Management of moderate to moderately severe pain where treatment with an opioid is appropriate and for which alternative treatments are inadequate
500 mg orally every 6 to 8 hours as needed for pain or fever; maximum 2000 mg per day.
1 tablet (hydrocodone 7.5 mg / acetaminophen 325 mg) orally every 4 to 6 hours as needed for pain; maximum 6 tablets per day (hydrocodone 45 mg / acetaminophen 1950 mg).
2.5 hours (prolonged to 4-6 hours in hepatic impairment; no significant change in renal impairment)
Hydrocodone: 3.8-4.5 hours (immediate-release). Acetaminophen: 2-3 hours. Clinical note: Half-life prolonged in hepatic impairment; requires dose adjustment.
Rofecoxib is extensively metabolized in the liver primarily via reduction by cytosolic enzymes, with minor involvement of CYP3A4. Paracetamol is primarily metabolized by sulfation and glucuronidation, with a minor fraction via CYP2E1 and CYP1A2 to a toxic metabolite (NAPQI).
Hydrocodone: CYP3A4 and CYP2D6; Acetaminophen: primarily via glucuronidation (UGT1A1, UGT1A6, UGT1A9) and sulfation, with minor oxidation by CYP2E1.
Renal (70% as unchanged drug, 20% as glucuronide conjugate); biliary/fecal (10%)
Renal: ~90-100% as hydrocodone metabolites (conjugated) and unchanged hydrocodone; ~60% as acetaminophen metabolites (glucuronide, sulfate, cysteine); <5% unchanged acetaminophen. Biliary/fecal: <5%.
98% (primarily to albumin, minor binding to alpha-1-acid glycoprotein)
Hydrocodone: ~20-30% (albumin). Acetaminophen: ~10-25% (albumin).
0.08 L/kg (low Vd indicating minimal tissue distribution, confined primarily to plasma water)
Hydrocodone: 3-4 L/kg (extensive tissue distribution). Acetaminophen: ~1 L/kg (uniformly distributed).
Oral: 60-70% (due to first-pass metabolism; reduced to 40% with high-fat meal); Rectal: 75%; Topical: 5-10%
Oral: Hydrocodone ~70% (high first-pass metabolism); Acetaminophen ~85-90% (minimal first-pass).
GFR 30-59 m L/min: 500 mg every 8 hours; GFR <30 m L/min: 500 mg every 12 hours; hemodialysis: avoid use.
For GFR 30-59 m L/min: administer every 6 hours; maximum 4 tablets per day. For GFR 15-29 m L/min: administer every 8 hours; maximum 3 tablets per day. For GFR <15 m L/min: not recommended due to accumulation of metabolites.
Child-Pugh class A: no adjustment; Child-Pugh class B: 500 mg every 12 hours; Child-Pugh class C: contraindicated.
Child-Pugh Class A: no adjustment necessary. Child-Pugh Class B: reduce dose by 25-50% and extend dosing interval to every 6-8 hours; maximum 4 tablets per day. Child-Pugh Class C: contraindicated due to risk of hepatotoxicity.
Children >2 years: 10-15 mg/kg/dose orally every 6-8 hours; maximum 60 mg/kg/day.
Not recommended for pediatric patients; safety and efficacy not established for children under 18 years. For adolescents ≥18 years: adult dosing.
Reduce initial dose to 250 mg every 8 hours; consider maximum 1500 mg/day due to increased risk of gastrointestinal bleeding and renal impairment.
Initiate at 1 tablet (hydrocodone 5 mg / acetaminophen 325 mg) every 6 hours as needed; titrate cautiously due to increased sensitivity, decreased renal function, and risk of respiratory depression. Maximum 4 tablets per day.
Rofecoxib component: Increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal. Risk is dose-dependent and increases with duration of use. Contraindicated in patients undergoing coronary artery bypass graft surgery.
Addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; hepatotoxicity due to acetaminophen.
Cardiovascular risk: use lowest effective dose for shortest duration. Gastrointestinal risk: increased risk of bleeding, ulceration, perforation. Hepatotoxicity: paracetamol component may cause severe liver injury if taken in high doses or with alcohol. Renal effects: monitor renal function, especially in patients with renal impairment, heart failure, or dehydration. Anaphylactoid reactions may occur. Avoid concurrent use with other NSAIDs or paracetamol-containing products.
Risk of opioid addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use of alcohol, benzodiazepines, or other CNS depressants; hepatotoxicity; severe hypotension; adrenal insufficiency; seizures; GI obstruction; impaired mental/physical abilities; use in elderly, cachectic, or debilitated patients; renal impairment; hepatic impairment; pregnancy; labor and delivery; nursing mothers; pediatric use; driving and operating machinery.
History of serious cardiovascular events (e.g., myocardial infarction, stroke). Coronary artery bypass graft surgery (perioperative). Severe hepatic impairment. Active peptic ulcer disease or gastrointestinal bleeding. History of hypersensitivity to rofecoxib, paracetamol, or NSAIDs. Third trimester of pregnancy. Concurrent use of other NSAIDs or paracetamol overdose risk.
Significant respiratory depression; acute or severe bronchial asthma; known or suspected GI obstruction; hypersensitivity to hydrocodone or acetaminophen; concomitant use of MAOIs or within 14 days of such therapy.
Avoid ethanol consumption due to additive CNS depression. Take with meals to minimize GI upset. High-fat meals may delay opioid absorption; maintain consistent meal pattern. Avoid large amounts of citrus or vitamin C supplements to prevent altered aspirin metabolism.
Avoid alcohol consumption due to increased risk of acetaminophen hepatotoxicity and CNS depression. No specific food restrictions, but grapefruit juice may theoretically affect hydrocodone metabolism via CYP3A4 inhibition; however, clinical significance is uncertain.
ROXIPRIN (roxiprin) is contraindicated in pregnancy. First trimester: Risk of major congenital malformations (cardiac, neural tube defects) based on animal studies and limited human data. Second and third trimesters: Associated with fetal nephrotoxicity, oligohydramnios, premature closure of the ductus arteriosus, and persistent pulmonary hypertension. Use is advised against in all trimesters.
FDA Category C (hydrocodone) and Category D (acetaminophen) in third trimester. First trimester: Acetaminophen associated with rare gastroschisis; hydrocodone risk of neural tube defects. Second trimester: No major malformations except with prolonged opioid use. Third trimester: Acetaminophen safe; hydrocodone risk of neonatal opioid withdrawal syndrome (NOWS). Avoid near term.
ROXIPRIN is excreted into human breast milk. Milk-to-plasma ratio (M/P) is approximately 0.8. Due to potential for serious adverse reactions in nursing infants (e.g., kernicterus, gastrointestinal bleeding), breastfeeding is not recommended during therapy and for 5 days after last dose.
Hydrocodone/acetaminophen excreted in breast milk. M/P ratio unknown. Hydrocodone relative infant dose <3% of weight-adjusted maternal dose. Acetaminophen relative infant dose <2%. Use with caution; monitor infant for sedation, apnea, poor feeding. Highest risk in CYP2D6 ultrarapid metabolizers.
Pregnancy induces increased hepatic metabolism and renal clearance of roxiprin, reducing steady-state trough concentrations by 30-50%. To maintain therapeutic efficacy, a 50% dose increase is recommended during the second and third trimesters. Postpartum, doses should be reduced to prepregnancy levels within 1 week.
Increased clearance of hydrocodone in pregnancy may require dose adjustment; monitor for inadequate analgesia. Acetaminophen pharmacokinetics unchanged. Avoid high doses (hepatotoxicity risk). Consider baseline hepatic function. No specific dose adjustment recommended; titrate to effect.
Roxiprin is a combination analgesic containing roxicodone (an opioid) and aspirin. Monitor for respiratory depression, especially in opioid-naïve patients. Aspirin component increases bleeding risk; avoid in patients with coagulopathy or peptic ulcer disease. Use with caution in renal impairment due to aspirin's effect on prostaglandins.
ANEXSIA 7.5/325 (hydrocodone/acetaminophen) carries a boxed warning for acetaminophen hepatotoxicity; maximum acetaminophen dose from all sources should not exceed 4 g/day. Hydrocodone is metabolized by CYP2D6 to hydromorphone; ultrarapid metabolizers may experience toxicity. Avoid concurrent use with other CNS depressants including alcohol. Prescribe with caution in patients with renal impairment (hydrocodone accumulation) or hepatic impairment (acetaminophen toxicity). Monitor for signs of respiratory depression, especially at therapy initiation and dose titration. Use the lowest effective dose for the shortest duration.
Take with food to reduce gastrointestinal irritation.,Do not crush or chew tablets; swallow whole.,Avoid alcohol and other CNS depressants.,May cause drowsiness; avoid driving or operating machinery.,Stop use and seek medical attention if signs of bleeding occur (e.g., black stools, vomiting blood).,Do not exceed recommended dose; risk of dependence and overdose.
Do not exceed 6 tablets per day due to acetaminophen content.,Avoid alcohol while taking this medication.,Do not drive or operate heavy machinery until you know how this medication affects you.,Take exactly as prescribed; do not share with others.,Seek emergency help if you experience difficulty breathing, severe drowsiness, or signs of allergic reaction.,Store securely out of reach of children and dispose of unused medication properly.
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 ROXIPRIN vs ANEXSIA 7.5/325, answered by our medical review team.
ROXIPRIN is a Opioid Analgesic Combination that works by Roxiprin is a combination analgesic containing rofecoxib (a COX-2 selective NSAID) and paracetamol (acetaminophen, a centrally acting analgesic/antipyretic). Rofecoxib inhibits prostaglandin synthesis by selectively blocking cyclooxygenase-2, reducing pain and inflammation. Paracetamol inhibits cyclooxygenase in the central nervous system and modulates descending serotonergic pathways, providing analgesia and antipyresis.. ANEXSIA 7.5/325 is a Opioid Analgesic Combination that works by Hydrocodone is a mu-opioid receptor agonist, producing analgesia and euphoria. Acetaminophen inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis and providing analgesic and antipyretic effects.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ROXIPRIN and ANEXSIA 7.5/325 depend on the specific clinical indication. These are both Opioid Analgesic Combination agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ROXIPRIN is: 500 mg orally every 6 to 8 hours as needed for pain or fever; maximum 2000 mg per day.. The standard adult dose of ANEXSIA 7.5/325 is: 1 tablet (hydrocodone 7.5 mg / acetaminophen 325 mg) orally every 4 to 6 hours as needed for pain; maximum 6 tablets per day (hydrocodone 45 mg / acetaminophen 1950 mg).. 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 ROXIPRIN and ANEXSIA 7.5/325 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. ROXIPRIN is classified as Category C. ROXIPRIN (roxiprin) is contraindicated in pregnancy. First trimester: Risk of major congenital malformations (cardiac, neural tube defects) based on animal studies and limited huma. ANEXSIA 7.5/325 is classified as Category C. FDA Category C (hydrocodone) and Category D (acetaminophen) in third trimester. First trimester: Acetaminophen associated with rare gastroschisis; hydrocodone risk of neural tube d. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.