Acetaminophen Pediatric Dose — Analgesia & Antipyresis
Acetaminophen (paracetamol) is a non-opioid analgesic and antipyretic that acts centrally by inhibiting prostaglandin synthesis in the CNS. It is one of the most widely used medications in pediatrics for the management of mild-to-moderate pain and fever across all age groups. Its availability in oral, rectal, and intravenous formulations makes it versatile for both inpatient and outpatient settings.
Pediatric Dosing
Oral and Rectal
- Oral: 15 mg/kg PO every 4 hours PRN, up to 5 doses per day
- Rectal: 20 mg/kg PR every 4 hours PRN, up to 5 doses per day
- Daily maximum: Not to exceed 75 mg/kg/day or 4 g/day, whichever is less
Intravenous (IV)
| Age / Weight Group | Dose | Frequency | Max Single Dose |
|---|---|---|---|
| <13 years | 15 mg/kg IV | Every 6 hours | 750 mg/dose |
| >13 years and <50 kg | 15 mg/kg IV | Every 6 hours | Consult institutional protocol |
| >13 years and ≥50 kg | 1000 mg IV (fixed dose) | Every 6 hours | 1000 mg/dose |
Worked Examples
Oral/PR example — 20 kg child: 20 kg × 15 mg/kg = 300 mg PO per dose (max daily dose: 20 kg × 75 mg/kg = 1500 mg/day). IV example — 30 kg child (<13 years): 30 kg × 15 mg/kg = 450 mg IV Q6H (well below the 750 mg/dose cap).
Consider all sources of acetaminophen when calculating the total daily dose to avoid inadvertent overdose.
Indications and Clinical Context
Acetaminophen is indicated for mild-to-moderate pain management and antipyresis in pediatric patients. It is a first-line analgesic in the pediatric setting due to its favorable safety profile when dosed appropriately and its lack of anti-platelet effects, making it preferable to NSAIDs in select populations (e.g., post-operative patients, those with bleeding risk). IV formulations are particularly useful in the perioperative setting or when enteral access is unavailable.
Acetaminophen is frequently incorporated into multimodal analgesia strategies in the PICU and perioperative environment to reduce opioid requirements. Clinicians should account for all concomitant acetaminophen-containing products (e.g., combination cough/cold preparations, opioid combination products) when calculating the total daily dose, as hepatotoxicity risk rises significantly with cumulative overdose.
Administration and Monitoring
Oral formulations are preferred when feasible; rectal bioavailability is lower and more variable, which is reflected in the higher PR dose of 20 mg/kg. IV acetaminophen should be infused over 15 minutes. The maximum single IV dose in patients under 13 years is 750 mg; doses should be weight-based up to this cap. For adolescents over 13 years weighing 50 kg or more, the adult fixed dose of 1000 mg IV Q6H applies.
- Daily dose ceiling: Do not exceed 75 mg/kg/day or 4 g/day (whichever is lower) across all routes combined
- Hepatotoxicity risk: Monitor for signs of liver injury with prolonged use or in patients with hepatic impairment or malnutrition
- Contraindications: Severe hepatic impairment; known hypersensitivity to acetaminophen
- Cumulative dosing: Always account for acetaminophen present in combination products before prescribing additional doses
Disclaimer: This article is an educational reference summarizing standard pediatric dosing values. It is not a substitute for clinical judgment. Always verify doses against institutional protocols, the current edition of authoritative references (e.g., Lexicomp, Harriet Lane Handbook, PALS guidelines), the patient’s accurate weight, and any patient-specific factors (renal/hepatic function, allergies, comedications) before administration.