ROXICET 5/500
Clinical safety rating
cautionComprehensive clinical and safety monograph for ROXICET 5/500 (ROXICET 5/500).
Oxycodone is a full opioid agonist that binds to mu-opioid receptors in the CNS, inhibiting ascending pain pathways and altering pain perception. Acetaminophen inhibits cyclooxygenase (COX) enzymes, primarily in the CNS, reducing prostaglandin synthesis and producing analgesic and antipyretic effects.
| Metabolism | Oxycodone is metabolized primarily via CYP3A4 and CYP2D6 to noroxycodone and oxymorphone. Acetaminophen is metabolized mainly via glucuronidation (UGT1A1, UGT1A6, UGT1A9) and sulfation, with minor oxidation by CYP2E1 and CYP1A2 producing N-acetyl-p-benzoquinone imine (NAPQI). |
| Excretion | Oxycodone: primarily hepatic metabolism to noroxycodone, oxymorphone, and conjugates; renal elimination of metabolites (about 60-87% as unchanged and metabolites), fecal < 10%. Acetaminophen: renal elimination of conjugates (90-100%), <5% unchanged. |
| Half-life | Oxycodone: 3-5 hours (immediate-release); Acetaminophen: 2-3 hours. In hepatic impairment, oxycodone half-life prolonged (up to 12-15 hours). |
| Protein binding | Oxycodone: ~45% bound to albumin; Acetaminophen: 10-25% bound to albumin. |
| Volume of Distribution | Oxycodone: 2-3 L/kg (extensive tissue distribution); Acetaminophen: 0.8-1.0 L/kg (distribution throughout body water). |
| Bioavailability | Oxycodone oral: 60-87% (high first-pass metabolism varies); Acetaminophen oral: 80-90%. |
| Onset of Action | Oral: oxycodone 10-15 minutes; acetaminophen 15-30 minutes. |
| Duration of Action | Oxycodone IR: 4-6 hours; acetaminophen: 4-6 hours. Clinical duration limited by oxycodone in fixed combination. |
| Molecular Weight | Oxycodone: 315.37 Da; Acetaminophen: 151.16 Da |
1-2 tablets (5-10 mg oxycodone / 325-650 mg acetaminophen) orally every 4-6 hours as needed for pain; maximum 12 tablets per day (60 mg oxycodone / 6000 mg acetaminophen) in 24 hours.
| Dosage form | TABLET |
| Renal impairment | CrCl 30-50 mL/min: administer every 6 hours. CrCl 10-29 mL/min: administer every 8 hours. CrCl <10 mL/min: use not recommended due to oxycodone accumulation; consider alternative. |
| Liver impairment | Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% and extend dosing interval to every 8 hours. Child-Pugh Class C: contraindicated due to acetaminophen hepatotoxicity. |
| Pediatric use | Not typically recommended; use weight-based dosing of oxycodone 0.1-0.2 mg/kg/dose (max 5 mg/dose) every 4-6 hours as needed, with acetaminophen component not to exceed 75 mg/kg/day. Not approved for children <12 years. |
| Geriatric use | Initiate at lowest dose (one tablet every 6 hours) and titrate cautiously. Monitor for respiratory depression, sedation, and constipation. Avoid doses >4 tablets per day unless tolerated. |
| 1st trimester | FDA category D. Risk of fetal harm; associated with neural tube defects and cardiac malformations. Use contraindicated unless no safer alternative. |
| 2nd trimester | FDA category D. Risk of fetal harm; may cause oligohydramnios and fetal renal dysfunction. Avoid use. |
| 3rd trimester | FDA category D and D. Near term, may cause respiratory depression, premature closure of ductus arteriosus, and persistent pulmonary hypertension in neonate. Avoid use. |
Clinical note
Comprehensive clinical and safety monograph for ROXICET 5/500 (ROXICET 5/500).
| Placental transfer | Both components cross the placenta. Oxycodone: significant transfer (fetal/maternal ratio ~0.7). Acetaminophen: readily crosses. |
| Breastfeeding | Oxycodone and acetaminophen are excreted into breast milk. Oxycodone concentrations are low but risk of infant respiratory depression exists. Use caution, monitor infant for drowsiness and breathing difficulties. Acetaminophen is considered compatible. |
| Lactation Rating | L3 (Moderately Safe) for oxycodone; L1 (Safe) for acetaminophen |
| Teratogenic Risk | Pregnancy Category C (oxycodone) and D (acetaminophen at high doses). Oxycodone: Risk of neonatal opioid withdrawal syndrome (NOWS) with prolonged use in third trimester; risk of respiratory depression near term. Acetaminophen: Epidemiologic data not conclusively linked to major malformations at therapeutic doses, but high doses may be associated with fetal hepatotoxicity. FDA warns against chronic use during pregnancy due to NOWS. |
| Fetal Monitoring | Maternal: Pain score, respiratory rate, sedation level, bowel function, liver function tests (acetaminophen). Fetal/Neonatal: Fetal heart rate monitoring if prolonged use near term; assess for NOWS (Neonatal Abstinence Score) in newborns. Consider umbilical cord drug testing if chronic use. |
| Fertility Effects | Oxycodone may impair fertility in females by disrupting menstrual cycles and ovulation via opioid receptor-mediated hypothalamic-pituitary-gonadal axis suppression. Acetaminophen: Limited evidence suggests possible prolongation of time to pregnancy with chronic use; mechanism unclear. Both may affect sperm parameters in males (decreased motility, count). |
■ FDA Black Box Warning
Addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion of even one dose of oxycodone, especially by children, can cause fatal overdose; neonatal opioid withdrawal syndrome; cytochrome P450 3A4 interaction with concurrent use of benzodiazepines or other CNS depressants; hepatotoxicity due to acetaminophen (dose-related).
| Serious Effects |
Hypersensitivity to oxycodone, acetaminophen, or any componentSevere respiratory depressionAcute or severe bronchial asthmaGI obstruction (e.g., paralytic ileus)Known or suspected gastrointestinal obstruction
| Precautions | Risk of opioid addiction, abuse, and misuse; life-threatening respiratory depression; risk of accidental ingestion; neonatal opioid withdrawal syndrome if used during pregnancy; risk of severe hypotension; risk of hepatotoxicity due to acetaminophen; risk of serotonin syndrome if co-administered with serotonergic drugs; adrenal insufficiency; risk of seizures; risk of increased intracranial pressure; severe renal or hepatic impairment; drug interactions with CNS depressants and CYP3A4 inhibitors/inducers. |
| Food/Dietary | Avoid alcohol and grapefruit juice. High-fat meals may delay absorption of oxycodone, but does not affect total exposure. |
| Clinical Pearls | ROXICET 5/500 contains oxycodone (5 mg) and acetaminophen (500 mg). The acetaminophen component limits total daily use to avoid hepatotoxicity; maximum 4 g/day from all sources. Oxycodone is a Schedule II controlled substance with high abuse potential. Use with caution in patients with respiratory compromise, head injury, or hepatic impairment. Coadministration with alcohol or other CNS depressants increases sedation and respiratory depression risk. Consider naloxone co-prescription for high-risk patients. |
| Patient Advice | Take only as prescribed; do not exceed 8 tablets in 24 hours due to acetaminophen. · Avoid alcohol and medications containing acetaminophen (e.g., Tylenol, cold remedies) to prevent liver damage. · Do not crush or chew tablets—swallow whole. · May cause drowsiness or dizziness; avoid driving or operating machinery until effects known. · Store securely out of reach of others; dispose of unused tablets via drug take-back program. · Do not share with others; misuse can cause addiction, overdose, or death. · Seek emergency help if signs of overdose: slow breathing, extreme drowsiness, confusion, or loss of consciousness. |
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