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Non-Opioid Analgesic / Antipyretic (IV) Pregnancy: Safe — paracetamol is the analgesic of choice in pregnancy at standard doses; short-term use acceptable.

Paracetamol IV (Burns Multimodal Analgesia)

Brand names: Perfalgan

Adult dose

Dose: 1000 mg IV over 15 minutes every 6 hours (regular, scheduled); weight <50 kg: 15 mg/kg IV (max 60 mg/kg/day)
Route: IV infusion over 15 minutes
Frequency: Every 6 hours (regular dosing — NOT PRN; scheduled around the clock preferred in burns)
Max: 4 g/day (weight ≥50 kg); 60 mg/kg/day (weight <50 kg, max 4 g)
IV paracetamol is the cornerstone of multimodal analgesia in burns — scheduled around the clock reduces opioid requirements by 20–30%, allowing lower opioid doses and reducing sedation. Burns patients often cannot absorb oral medications reliably (GI oedema, fluid shifts) — IV formulation essential during acute phase. Background analgesia also reduces procedural pain burden.

Paediatric dose

Dose: 15 mg/kg
Route: IV over 15 minutes
Frequency: Every 4–6 hours
Max: 60 mg/kg/day (max 4 g/day)
Neonates (32–44 weeks corrected): 7.5 mg/kg every 6–8 hours. Children 28–32 weeks corrected gestation: 7.5 mg/kg every 12 hours. BNFc dose tables by weight and gestational age.

Dose adjustments

Renal

No dose adjustment for eGFR >30. Severe renal failure: extend dosing interval to 8 hours and monitor.

Hepatic

Avoid in severe hepatic impairment (Child-Pugh C) — dramatically reduced glutathione stores increase hepatotoxicity risk at standard doses. Moderate impairment: max 3 g/day, reduce dosing interval.

Paediatric weight-based calculator

Neonates (32–44 weeks corrected): 7.5 mg/kg every 6–8 hours. Children 28–32 weeks corrected gestation: 7.5 mg/kg every 12 hours. BNFc dose tables by weight and gestational age.

Clinical pearls

  • MHRA warning — flucloxacillin-paracetamol HOGW acidosis: this combination (common in burns patients — flucloxacillin for wound prophylaxis + paracetamol IV) has been linked to high-anion gap metabolic acidosis of unclear mechanism; MHRA 2021 updated guidance — monitor acid-base status in patients on prolonged combined therapy
  • Scheduled around-the-clock dosing superiority: PRN paracetamol is inferior to scheduled dosing in burns — background pain is constant; scheduled 4× daily IV paracetamol provides sustained plasma levels and reduces opioid consumption; BBA guidelines recommend scheduled rather than PRN
  • Oral vs IV in acute burns: during the acute phase (first 48–72h) with GI oedema, ileus, and fluid shifts — oral absorption is unreliable; IV formulation preferred until GI function normalises; then step down to oral. Cost: IV paracetamol is significantly more expensive than oral — use only when genuinely indicated

Contraindications

  • Severe hepatic impairment
  • Paracetamol hypersensitivity
  • Concomitant paracetamol in any form (combination products — risk of accidental overdose)

Side effects

  • Hepatotoxicity (overdose or severe hepatic impairment — dose-dependent; via NAPQI metabolite)
  • Hypotension (during IV infusion — uncommon; due to vasodilation)
  • Elevated LFTs (rarely at standard doses)
  • Thrombocytopenia (very rare)

Interactions

  • Warfarin (paracetamol >2 g/day regularly raises INR via reduction of clotting factor synthesis — monitor INR in burns patients on warfarin)
  • Hepatotoxic drugs (alcohol, isoniazid, rifampicin — increase NAPQI production; reduce daily limit)
  • Flucloxacillin (IV flucloxacillin plus paracetamol — HOGW syndrome: high anion gap metabolic acidosis; mechanism unclear; monitor in burns patients on both)

Monitoring

  • Daily paracetamol dose (cumulative — check all sources; multimodal regimens often include combination products)
  • LFTs (especially if hepatic risk factors or flucloxacillin co-prescription)
  • Acid-base status (HOGW acidosis signal with flucloxacillin combination)
  • Pain scores (efficacy assessment)

Reference: BNFc; BNF 90; BNFc; British Burns Association Analgesia Guidelines 2018; MHRA Drug Safety Update 2021 (flucloxacillin + paracetamol); NICE NG24 (Burns). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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