ROXICET

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ROXICET (ROXICET).

How it works

Roxicet is a combination of oxycodone, a full mu-opioid receptor agonist, and acetaminophen, which inhibits cyclooxygenase (COX) enzymes, primarily in the central nervous system, to reduce pain perception and fever.

What the body does with it

Metabolism	Oxycodone is primarily metabolized by CYP3A4 and to a lesser extent by CYP2D6; acetaminophen is metabolized via conjugation (glucuronidation and sulfation) and by CYP2E1 (minor, but produces toxic NAPQI).
Excretion	Primarily renal (90% as glucuronide conjugates, <10% unchanged). Biliary/fecal excretion is minor (<5%).
Half-life	Oxycodone: 3-5 hours (immediate-release); prolonged in hepatic/renal impairment. Acetaminophen: 2-3 hours.
Protein binding	Oxycodone: 45-50% (primarily albumin). Acetaminophen: 10-25% (minimal).
Volume of Distribution	Oxycodone: 2.6 L/kg; large Vd indicates extensive tissue distribution.
Bioavailability	Oral oxycodone: 60-87%; Acetaminophen: 75-85%.
Onset of Action	Oral: 15-30 minutes for oxycodone; peak effect 1 hour.
Duration of Action	Immediate-release: 4-6 hours for oxycodone; acetaminophen duration 4-6 hours.

Classification & Brands

Dosing & administration

1-2 tablets (oxycodone 5-10 mg/acetaminophen 325-650 mg) orally every 4-6 hours as needed for pain; maximum acetaminophen 4000 mg/day (3000 mg/day in high-risk patients).

Dosage form	TABLET
Renal impairment	eGFR 30-60 mL/min: reduce dose to 50-75% of usual. eGFR 10-29 mL/min: reduce dose to 25-50% of usual. eGFR <10 mL/min: avoid use or use with extreme caution; reduce dose to 25% and extend dosing interval to every 8-12 hours.
Liver impairment	Child-Pugh Class A: no adjustment necessary. Child-Pugh Class B: reduce starting dose by 50% (e.g., oxycodone 2.5-5 mg) and monitor. Child-Pugh Class C: avoid use or use with extreme caution; reduce dose to 25% and extend interval.
Pediatric use	Weight-based: oxycodone 0.05-0.15 mg/kg per dose, acetaminophen 10-15 mg/kg per dose, orally every 4-6 hours as needed; maximum acetaminophen 75 mg/kg/day (not to exceed 4000 mg/day) in children ≥12 years; for children <12 years, max acetaminophen 75 mg/kg/day (max 325 mg per dose in children <6 years).
Geriatric use	Start with lowest available dose (oxycodone 2.5-5 mg); consider extended dosing interval (every 6-8 hours); monitor renal and hepatic function; avoid in patients with advanced liver disease or GFR <30 mL/min.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ROXICET (ROXICET).

Breastfeeding	Oxycodone is excreted into breast milk; M/P ratio ~3.4 (for oxycodone). Relative infant dose 1.7-6.8% of maternal weight-adjusted dose; may cause infant sedation, respiratory depression, and withdrawal. Use with caution, monitor infant for somnolence and feeding difficulties; avoid if mother is on high doses or has CYP2D6 ultra-rapid metabolizer status.
Teratogenic Risk	Pregnancy Category D (FDA). First trimester: Risk of neural tube defects and congenital anomalies with chronic use; no adequate studies. Second trimester: Continued risk of fetal dependence and withdrawal; growth restriction possible. Third trimester: High risk of neonatal opioid withdrawal syndrome (NOWS), respiratory depression, and preterm birth; avoid prolonged use.

Warnings & precautions

■ FDA Black Box Warning

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 associated with acetaminophen.

Side Effect Profile

Serious Effects

Absolute Contraindications

Significant respiratory depression; acute or severe bronchial asthma; known hypersensitivity to oxycodone, acetaminophen, or any component; suspected or known gastrointestinal obstruction (e.g., paralytic ileus); severe hepatic impairment.

Clinical Precautions

Precautions

Respiratory depression; increased intracranial pressure; severe hypotension; hepatotoxicity (acetaminophen); opioid-induced hyperalgesia; adrenal insufficiency; severe hypotension; risks of use in patients with gastrointestinal obstruction; seizures; severe renal impairment.

Clinical Tips & Counseling

Drug interactions

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ROXICET

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ROXICET (ROXICET).

How it works

What the body does with it

Metabolism	Oxycodone is primarily metabolized by CYP3A4 and to a lesser extent by CYP2D6; acetaminophen is metabolized via conjugation (glucuronidation and sulfation) and by CYP2E1 (minor, but produces toxic NAPQI).
Excretion	Primarily renal (90% as glucuronide conjugates, <10% unchanged). Biliary/fecal excretion is minor (<5%).
Half-life	Oxycodone: 3-5 hours (immediate-release); prolonged in hepatic/renal impairment. Acetaminophen: 2-3 hours.
Protein binding	Oxycodone: 45-50% (primarily albumin). Acetaminophen: 10-25% (minimal).
Volume of Distribution	Oxycodone: 2.6 L/kg; large Vd indicates extensive tissue distribution.
Bioavailability	Oral oxycodone: 60-87%; Acetaminophen: 75-85%.
Onset of Action	Oral: 15-30 minutes for oxycodone; peak effect 1 hour.
Duration of Action	Immediate-release: 4-6 hours for oxycodone; acetaminophen duration 4-6 hours.

Classification & Brands

Dosing & administration

1-2 tablets (oxycodone 5-10 mg/acetaminophen 325-650 mg) orally every 4-6 hours as needed for pain; maximum acetaminophen 4000 mg/day (3000 mg/day in high-risk patients).

Dosage form	TABLET
Renal impairment	eGFR 30-60 mL/min: reduce dose to 50-75% of usual. eGFR 10-29 mL/min: reduce dose to 25-50% of usual. eGFR <10 mL/min: avoid use or use with extreme caution; reduce dose to 25% and extend dosing interval to every 8-12 hours.
Liver impairment	Child-Pugh Class A: no adjustment necessary. Child-Pugh Class B: reduce starting dose by 50% (e.g., oxycodone 2.5-5 mg) and monitor. Child-Pugh Class C: avoid use or use with extreme caution; reduce dose to 25% and extend interval.
Pediatric use	Weight-based: oxycodone 0.05-0.15 mg/kg per dose, acetaminophen 10-15 mg/kg per dose, orally every 4-6 hours as needed; maximum acetaminophen 75 mg/kg/day (not to exceed 4000 mg/day) in children ≥12 years; for children <12 years, max acetaminophen 75 mg/kg/day (max 325 mg per dose in children <6 years).
Geriatric use	Start with lowest available dose (oxycodone 2.5-5 mg); consider extended dosing interval (every 6-8 hours); monitor renal and hepatic function; avoid in patients with advanced liver disease or GFR <30 mL/min.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ROXICET (ROXICET).

Breastfeeding	Oxycodone is excreted into breast milk; M/P ratio ~3.4 (for oxycodone). Relative infant dose 1.7-6.8% of maternal weight-adjusted dose; may cause infant sedation, respiratory depression, and withdrawal. Use with caution, monitor infant for somnolence and feeding difficulties; avoid if mother is on high doses or has CYP2D6 ultra-rapid metabolizer status.
Teratogenic Risk	Pregnancy Category D (FDA). First trimester: Risk of neural tube defects and congenital anomalies with chronic use; no adequate studies. Second trimester: Continued risk of fetal dependence and withdrawal; growth restriction possible. Third trimester: High risk of neonatal opioid withdrawal syndrome (NOWS), respiratory depression, and preterm birth; avoid prolonged use.