ROXIPRIN
Clinical safety rating
cautionComprehensive clinical and safety monograph for ROXIPRIN (ROXIPRIN).
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.
| Metabolism | 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). |
| Excretion | Renal (70% as unchanged drug, 20% as glucuronide conjugate); biliary/fecal (10%) |
| Half-life | 2.5 hours (prolonged to 4-6 hours in hepatic impairment; no significant change in renal impairment) |
| Protein binding | 98% (primarily to albumin, minor binding to alpha-1-acid glycoprotein) |
| Volume of Distribution | 0.08 L/kg (low Vd indicating minimal tissue distribution, confined primarily to plasma water) |
| Bioavailability | Oral: 60-70% (due to first-pass metabolism; reduced to 40% with high-fat meal); Rectal: 75%; Topical: 5-10% |
| Onset of Action | Oral: 30-45 minutes; Intravenous: 5-10 minutes; Topical: 2-4 hours |
| Duration of Action | Oral: 4-6 hours (dose-dependent; extended-release formulations provide 12-hour coverage); Intravenous: 3-4 hours |
| Molecular Weight | 242.28 |
500 mg orally every 6 to 8 hours as needed for pain or fever; maximum 2000 mg per day.
| Dosage form | TABLET |
| Renal impairment | GFR 30-59 mL/min: 500 mg every 8 hours; GFR <30 mL/min: 500 mg every 12 hours; hemodialysis: avoid use. |
| Liver impairment | Child-Pugh class A: no adjustment; Child-Pugh class B: 500 mg every 12 hours; Child-Pugh class C: contraindicated. |
| Pediatric use | Children >2 years: 10-15 mg/kg/dose orally every 6-8 hours; maximum 60 mg/kg/day. |
| Geriatric use | Reduce initial dose to 250 mg every 8 hours; consider maximum 1500 mg/day due to increased risk of gastrointestinal bleeding and renal impairment. |
| 1st trimester | Contraindicated due to risk of fetal hemorrhage and premature closure of ductus arteriosus. |
| 2nd trimester | Contraindicated due to risk of fetal hemorrhage and premature closure of ductus arteriosus. |
| 3rd trimester | Contraindicated due to risk of fetal hemorrhage and premature closure of ductus arteriosus. |
Clinical note
Comprehensive clinical and safety monograph for ROXIPRIN (ROXIPRIN).
| Placental transfer | Crosses placenta; fetal plasma concentrations may approach maternal levels. |
| Breastfeeding | Excreted into breast milk in low amounts; however, due to potential adverse effects (e.g., platelet dysfunction, renal impairment) in infants, use is not recommended unless essential. |
| Lactation Rating | L5 - Contraindicated |
| Teratogenic Risk | 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. |
| Fetal Monitoring | Maternal: Complete blood count, liver function tests, renal function, and blood pressure monthly. Fetal: Ultrasound every 4-6 weeks for growth restriction and amniotic fluid index; fetal echocardiography at 20-24 weeks for ductus arteriosus patency. Assess for preterm labor symptoms. |
| Fertility Effects | ROXIPRIN impairs fertility in both males and females. In males: Reversible oligospermia and reduced sperm motility. In females: Disruption of ovulation and menstrual cycle irregularities. Effects may persist for several months after discontinuation. |
■ FDA Black Box Warning
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.
| Serious Effects |
Active peptic ulcer diseaseSevere hepatic impairmentThird trimester of pregnancyHypersensitivity to roxiprin or other NSAIDsHistory of aspirin-exacerbated respiratory diseaseHemorrhagic diathesis
| Precautions | 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. |
| Food/Dietary | 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. |
| Clinical Pearls | 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. |
| Patient Advice | 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. |
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