Antipyretic Choice After PCM Overdose in a 2-Year-Old

The Core Problem: Why Not Give Paracetamol Again?

• Initial symptoms (nausea, vomiting): 0-24 hours
• Hepatic necrosis begins: 24-36 hours post-ingestion
• Peak liver injury: 72-96 hours post-ingestion
• This child is currently in the window of maximum potential liver injury

What to Give for Fever

Option 1 - Ibuprofen (Preferred when liver injury cannot be excluded)

• Dose: 10 mg/kg PO every 6-8 hours
• Maximum: 40 mg/kg/day
• Ibuprofen is a safe, effective antipyretic and has no hepatotoxic burden
• A 2-year-old is well above the 6-month minimum age for ibuprofen use
• Do NOT use in children under 6 months (Rosen's Emergency Medicine)

Option 2 - Paracetamol at therapeutic dose (Only if LFTs are normal)

• If AST, ALT, bilirubin, and INR are all normal at 48 hours post-overdose, this is reassuring
• In that case, cautious re-use of paracetamol at standard therapeutic dose (10-15 mg/kg every 4-6 hours, max 75 mg/kg/day) is acceptable
• However, given the uncertainty, many clinicians prefer ibuprofen as the safer choice in this window

Avoid Aspirin Completely

• Aspirin is absolutely contraindicated in children under 15 years due to Reye syndrome risk (Rosen's Emergency Medicine).

Practical Summary

Bottom Line

• Ibuprofen 10 mg/kg PO q6-8h is the drug of choice for fever management
• Paracetamol should be withheld until liver injury is excluded by normal LFTs
• Ensure the child is adequately hydrated before giving ibuprofen
• The fever itself may be a sign of early hepatitis - this must be distinguished from infectious fever. Consult a pediatric gastroenterologist/hepatologist if LFTs are elevated

Mefenamic Acid as an Alternative Antipyretic in This Child

Short answer: Yes, it is a reasonable alternative in this context

Age Safety: Is a 2-year-old eligible?

Dose

• 5 mg/kg every 8 hours (three times daily) - preferred dose per MAPP Consensus 2025 with 95% level of agreement
• Range cited in studies: 4-6.5 mg/kg per dose, three times daily
• Total daily dose: ~19.5 mg/kg/day (Pfizer labeling for children)
• For a typical 12-13 kg child at 2 years: approximately 60-65 mg per dose
• Give as oral suspension (preferred for children under 12 years)
• Give with food to minimize GI irritation
• Duration: short-term only (no more than a few days for fever)

Hepatotoxicity Risk: Is it safer than ibuprofen for the liver?

• In a systematic review of NSAID hepatotoxicity in RCTs (PMC5820561), no studies reported hepatotoxicity from mefenamic acid - only diclofenac, celecoxib, and etoricoxib showed clinically significant hepatotoxicity
• NIH LiverTox database notes that across multiple large NSAID liver injury databases (US, Italy, Latin America), mefenamic acid appears in none of the NSAID hepatotoxicity case lists, while ibuprofen does (at low frequency)
• Like other NSAIDs, it CAN cause idiosyncratic liver injury at supratherapeutic doses, but at therapeutic doses the hepatotoxicity signal is minimal

Caveats (same as ibuprofen - class effects)

• Ensure adequate hydration - renal perfusion can be compromised by any NSAID during fever/dehydration. This is the most important precaution in a 2-year-old
• Watch for GI irritation (give with food)
• Avoid if the child has any renal impairment
• Do NOT use aspirin (Reye syndrome risk)
• Check LFTs before/during use if liver injury from overdose is not yet excluded

Practical Hierarchy for This Child

Dicyclomine (Dicycloverine) - Toxic Dose & Overdose

Therapeutic Doses (for context)

Toxic/Lethal Doses - What the Data Shows

• Acute oral LD₅₀ in mice: 625 mg/kg

• Maximum recorded oral dose in a 10-month-old child: 600 mg - survived
• Maximum recorded oral dose in an adult: ~1500 mg - survived
• These are the highest documented single ingestions with survival; no precise lethal human dose has been formally defined

• Fatal cases have occurred in infants at much lower doses
• Blood concentrations in 3 infants who died: 200, 220, and 505 ng/mL
• A 45-day-old infant (case report, 2026) developed tonic-clonic seizures, tachycardia, tachypnea, and died from central apnea and cardiovascular collapse - even at doses as low as 0.5 to 1 mg in very young infants, severe toxicity and death have been reported
• Infants have an immature blood-brain barrier, making them disproportionately vulnerable to CNS toxicity at doses that would be sub-toxic in older children or adults

Signs and Symptoms of Toxicity

• Curare-like neuromuscular blockade - unique to dicyclomine among anticholinergics; can cause muscular weakness progressing to paralysis at high doses (this is NOT typical of atropine or hyoscine)
• CNS: Stimulation first (seizures, agitation) followed by depression, coma
• Psychotic symptoms: disorientation, hallucinations, delusions, restlessness

Management of Overdose

1. Decontamination - Gastric lavage + activated charcoal (if within time window and patient is alert)
2. Supportive care - Maintain airway, IV fluids for shock
3. Sedation - Benzodiazepines or short-acting barbiturates for agitation/seizures
4. Specific antidote - Physostigmine
   • Indicated for pure anticholinergic toxicity with significant CNS symptoms
   • Adults: 1-2 mg IV by slow infusion (repeat after 30 min if symptoms recur)
   • Pediatric: 0.02 mg/kg IV, max 0.5 mg per dose
   • Keep atropine at bedside (to reverse physostigmine bradycardia)
   • Do NOT use if TCA co-ingestion suspected (risk of asystole)
5. Urinary retention - catheterization if needed
6. Mydriasis - pilocarpine eye drops (symptomatic)
7. Hyperthermia - active cooling

Special Danger Populations

• Infants under 6 months - ABSOLUTELY CONTRAINDICATED; risk of sudden apnea and death even at therapeutic-range doses; immature BBB allows excessive CNS penetration
• Elderly - heightened anticholinergic sensitivity, cognitive toxicity
• Myasthenia gravis - the curare-like effect is particularly dangerous
• Renal impairment - drug is substantially renally excreted; toxicity accumulates