TYLOX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TYLOX (TYLOX).
Tylox combines oxycodone, a mu-opioid receptor agonist, with acetaminophen, which inhibits cyclooxygenase (COX) and modulates descending serotonergic pathways.
| Metabolism | Oxycodone is metabolized primarily via CYP3A4 and CYP2D6; acetaminophen is metabolized in the liver via conjugation (glucuronidation, sulfation) and CYP2E1 for a minor toxic metabolite (NAPQI). |
| Excretion | Renal: oxycodone ~19% unchanged; acetaminophen ~2-5% unchanged. Biliary: minimal. Fecal: <5% total. Total renal elimination: ~60-70% as metabolites of oxycodone (noroxycodone, oxymorphone) and acetaminophen conjugates. |
| Half-life | Oxycodone: 3.5-5.6 hours; acetaminophen: 2-3 hours. In hepatic impairment, oxycodone half-life prolonged up to 13 hours. |
| Protein binding | Oxycodone: 38-45% primarily to albumin; acetaminophen: 10-25%. |
| Volume of Distribution | Oxycodone: 2.6 L/kg (large, indicates extensive tissue distribution); acetaminophen: 0.9 L/kg. |
| Bioavailability | Oral: oxycodone 60-87% (first-pass metabolism); acetaminophen 63-89%. |
| Onset of Action | Oral: 15-30 minutes; peak analgesia: 60-90 minutes. |
| Duration of Action | 3-6 hours (immediate-release); longer with controlled-release formulations (not applicable to Tylox). |
| Molecular Weight | Acetaminophen: 151.16 Da; Oxycodone: 315.36 Da. Tylex combination: each component's MW. |
1-2 capsules (oxycodone 5 mg/acetaminophen 325 mg) orally every 6 hours as needed for pain; maximum 12 capsules per day.
| Dosage form | CAPSULE |
| Renal impairment | GFR 30-50 mL/min: administer 75% of usual dose every 6 hours; GFR 10-29 mL/min: 50% of usual dose every 6 hours; GFR <10 mL/min: 25-50% of usual dose every 12 hours. |
| Liver impairment | Child-Pugh A: reduce dose by 50% and consider extended interval; Child-Pugh B: 25-50% of usual dose every 8-12 hours; Child-Pugh C: contraindicated or use with extreme caution at 25% of dose every 12 hours. |
| Pediatric use | Children ≥11 years: 1 capsule (oxycodone 5 mg/acetaminophen 325 mg) orally every 6 hours as needed; maximum 4 doses per day. For children <11 years: weight-based dosing of oxycodone 0.05-0.15 mg/kg/dose (max 5 mg) and acetaminophen 10-15 mg/kg/dose (max 650 mg) every 4-6 hours; use appropriate separate formulations. |
| Geriatric use | Initiate at 50% of adult dose (e.g., 1 capsule every 8-12 hours) and titrate cautiously due to increased sensitivity and risk of adverse effects; monitor renal and hepatic function. |
| 1st trimester | Contraindicated: risk of neural tube defects and cardiovascular malformations with first-trimester exposure to acetaminophen-oxycodone combination. Oxycodone is a pregnancy category C/D. |
| 2nd trimester | Caution: Use only if potential benefit justifies risk. Acetaminophen is generally considered safe; oxycodone may cause fetal dependence and withdrawal. Prolonged use may lead to neonatal opioid withdrawal syndrome (NOWS). |
| 3rd trimester | Contraindicated: High risk of neonatal opioid withdrawal syndrome, respiratory depression, and preterm labor. Acetaminophen overdose can cause fetal hepatotoxicity. |
Clinical note
Comprehensive clinical and safety monograph for TYLOX (TYLOX).
| Placental transfer | Both components cross the placenta. Acetaminophen: readily crosses, fetal levels similar to maternal. Oxycodone: rapid placental transfer; fetal concentrations may reach 60-100% of maternal levels. |
| Breastfeeding |
■ FDA Black Box Warning
Risk of addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; interactions with CNS depressants; and hepatotoxicity from acetaminophen overdose.
| Serious Effects |
Known hypersensitivity to acetaminophen or oxycodoneSevere respiratory depressionAcute or severe bronchial asthmaParalytic ileusSuspected surgical abdomen (until diagnosis confirmed)Concurrent use of MAO inhibitors or within 14 daysAlcoholism (risk of acetaminophen hepatotoxicity)
| Precautions | Risk of respiratory depression, opioid-induced hyperalgesia, hypotension, adrenal insufficiency, serotonin syndrome, severe hypotension, and hepatotoxicity; avoid abrupt discontinuation; use with caution in elderly, debilitated, or those with pulmonary disease. |
| Food/Dietary | Avoid alcohol. Grapefruit juice may increase oxycodone levels; limit or avoid consumption. High-fat meals may delay absorption but do not significantly alter overall exposure. |
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| Both acetaminophen and oxycodone are excreted into breast milk. Oxycodone levels are low but may cause infant sedation, respiratory depression, or dependence. Caution recommended; monitor infant for drowsiness and feeding difficulties. The American Academy of Pediatrics considers acetaminophen compatible with breastfeeding; oxycodone is usually compatible with caution. |
| Lactation Rating | L3 (Moderately Safe) – Oxycodone; L1 (Safe) for acetaminophen component. Overall L3 due to opioid. |
| Teratogenic Risk | Pregnancy Category C. First trimester: acetaminophen is generally considered safe; oxycodone has shown teratogenic effects in animal studies at high doses, but human data are limited. Second and third trimesters: chronic oxycodone use may lead to neonatal opioid withdrawal syndrome (NOWS). There is no evidence of major malformations with standard therapeutic doses. |
| Fetal Monitoring | Monitor maternal respiratory rate, sedation level, and bowel function. Assess fetal heart rate and uterine activity if used during labor. For chronic use, monitor for signs of opioid dependence and withdrawal in both mother and neonate. Perform newborn assessment for NOWS (e.g., Finnegan scores) if maternal use in late pregnancy. |
| Fertility Effects | Opiates can disrupt hypothalamic-pituitary-gonadal axis, leading to decreased libido, erectile dysfunction, and menstrual irregularities. Acetaminophen is not known to affect fertility at therapeutic doses. Limited data on combined effects; theoretical risk of opioid-induced hypogonadism with chronic high-dose oxycodone. |
| Clinical Pearls | Avoid concurrent use with other acetaminophen-containing products to prevent hepatotoxicity. Maximum acetaminophen dose is 4 g/day (3 g/day in chronic alcohol use). Monitor for respiratory depression, especially in elderly or opioid-naive patients. Use with caution in patients with hepatic impairment or severe renal dysfunction. Oxycodone has abuse potential; prescribe smallest quantity for shortest duration. |
| Patient Advice | Take exactly as prescribed; do not increase dose or frequency without consulting your doctor. · Do not take with other acetaminophen products (e.g., Tylenol, cold medications) to avoid liver damage. · Avoid alcohol while taking TYLOX; it increases risk of liver injury. · May cause drowsiness or dizziness; avoid driving or operating machinery until you know how TYLOX affects you. · Store securely away from children; accidental overdose can be fatal. · Do not share this medication with others; it can cause serious harm or addiction. · If you miss a dose, skip it and take next dose at regular time; do not double dose. · Seek emergency help if you experience slow breathing, severe drowsiness, or fainting. |