TAPENTADOL
Clinical safety rating: safe
Animal studies have demonstrated safety
Tapentadol is a centrally acting analgesic with a dual mechanism of action: mu-opioid receptor agonist and norepinephrine reuptake inhibitor.
| Metabolism | Extensively metabolized via conjugation (primarily glucuronidation) and by CYP2C9 and CYP2C19 to a minor extent. Major metabolites are inactive. |
| Excretion | Primarily renal: approximately 95% of the dose is excreted in urine (60% as tapentadol glucuronide, 15% as unchanged tapentadol, and 20% as other metabolites); less than 3% excreted in feces. |
| Half-life | Terminal elimination half-life is approximately 4 hours (range 3-5 hours) for immediate-release; for extended-release, effective half-life is about 4-6 hours due to prolonged absorption. |
| Protein binding | Approximately 20% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | 540 L (approximately 7.7 L/kg for a 70 kg adult), indicating extensive tissue distribution. |
| Bioavailability | Oral: approximately 32% due to first-pass metabolism; intravenous: 100%. |
| Onset of Action | Immediate-release: 30-60 minutes; Extended-release: not applicable (designed for sustained effect). |
| Duration of Action | Immediate-release: 4-6 hours; Extended-release: 12 hours. Analgesic effect correlates with plasma concentrations. |
Immediate-release tablets: 50-100 mg orally every 4-6 hours as needed for pain; maximum 600 mg per day. Extended-release tablets: 50-250 mg orally twice daily (every 12 hours); maximum 500 mg per day.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | Creatinine clearance (CrCl) 30-80 mL/min: No adjustment needed. CrCl <30 mL/min: Not recommended (extended-release) or use with caution and reduce dose by 50% (immediate-release). Hemodialysis: Not recommended. |
| Liver impairment | Child-Pugh Class A: No adjustment. Child-Pugh Class B: Reduce dose by 50% and increase dosing interval to every 8 hours (immediate-release) or every 12 hours (extended-release). Child-Pugh Class C: Contraindicated. |
| Pediatric use | Safety and efficacy not established in children <18 years; not recommended. |
| Geriatric use | Start at low end of dosing range; monitor for CNS effects, constipation, and respiratory depression. Immediate-release: 50 mg every 6 hours initially; extended-release: not recommended for opioid-naïve elderly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
CNS depressants including alcohol and benzodiazepines increase sedation risk MAOIs can cause serotonin syndrome.
| Breastfeeding | Excreted into breast milk in low concentrations (M/P ratio approximately 0.8). Infant exposure is low but may cause sedation or respiratory depression in neonates, especially with high maternal doses or prolonged use. Caution advised; monitor infant for signs of sedation or poor feeding. |
| Teratogenic Risk | First trimester: Limited data, no clear evidence of major malformations in humans, but opioid use associated with neural tube defects in some studies. Second and third trimesters: Chronic use may lead to fetal opioid dependence and neonatal opioid withdrawal syndrome (NOWS). Avoid prolonged use near term due to risk of respiratory depression at birth. |
■ FDA Black Box Warning
Risk of addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; and interactions with drugs affecting cytochrome P450 isoenzymes.
| Common Effects | Constipation |
| Serious Effects |
Significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or in absence of resuscitative equipment; known or suspected gastrointestinal obstruction; concurrent use of MAOIs or within 14 days; hypersensitivity to tapentadol.
| Precautions | Addiction, abuse, and misuse; life-threatening respiratory depression; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; severe hypotension; seizures; risk of serotonin syndrome; adrenal insufficiency; and withdrawal. |
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| Fetal Monitoring | Monitor for maternal sedation, respiratory depression, and constipation. Fetal monitoring: assess fetal growth and amniotic fluid volume if used chronically. Neonatal monitoring: observe for signs of opioid withdrawal (e.g., tremors, irritability, poor feeding) following prolonged in utero exposure. |
| Fertility Effects | Animal studies show no significant impairment of fertility at therapeutic doses. In humans, chronic opioid use may disrupt hormonal regulation (e.g., decreased libido, menstrual irregularities) but effects are reversible upon discontinuation. |