Section 13 · Monograph
Acetaminophen IV
Reviewed Nov 2026FDA label
OfirmevAnalgesic / antipyretic
- Forms
- IV: 1,000mg/100mL
- Dose
- Fever or pain: 1,000mg every 6 hours (or 650mg every 4 hours), max 4g/day; under 50kg 15mg/kg, max 75mg/kg/day
- MOA
- Central COX inhibition; antipyretic hypothalamic effect
Black Box Warning
- Risk of medication errors (confusion between mg and mL) and hepatotoxicity, including acute liver failure, at doses above the maximum recommended daily dose
Indications
- Management of mild to moderate pain; management of moderate to severe pain with adjunctive opioids; reduction of feverFDA-labeled
Off-Label Uses
- Fever control in neurocritical care and targeted temperature managementOff-label
Mechanism of Action
- Central COX inhibition and modulation of descending serotonergic pathways produces analgesia; hypothalamic action produces antipyresis
Full Dosing
Adult / usual
- Under 50kg: 15mg/kg every 6 hours (or 12.5mg/kg every 4 hours); maximum 75mg/kg/day
- Infuse over 15 minutes; account for all acetaminophen sources
Hepatic
- Adults and adolescents 50kg or more: 1,000mg every 6 hours or 650mg every 4 hours; maximum 4g/day (consider lower maximum with hepatic risk)
Contraindications
- Known hypersensitivity to acetaminophen
- Severe hepatic impairment or severe active liver disease
Drug Interactions
- Other acetaminophen-containing products: cumulative hepatotoxicity risk
- Warfarin: INR may rise with sustained use
- Enzyme inducers (carbamazepine, phenytoin, isoniazid) increase toxic metabolite formation
Adverse Effects
- Hepatotoxicity with overdose or at-risk patients (alcohol use, malnutrition, hepatic disease)
- Hypotension (during infusion in critically ill patients)
- Nausea, headache
- Rare serious skin reactions and hypersensitivity
Monitoring Parameters
- Liver function tests with prolonged use or risk factors
- Temperature and hemodynamics during infusion
- Total daily acetaminophen dose
Pregnancy & Lactation
- Considered acceptable in pregnancy at recommended doses
- Compatible with breastfeeding