Poisoning & Overdose

1 · First minutes

1. ABCDE first; never delay glucose.
2. Name the toxidrome: vitals, pupils, skin, bowel, temperature.
3. Paracetamol and salicylate in every deliberate overdose; NAC on timing and probability, not symptoms.

3 · Immediate workup

• Glucose (never delay), ECG (QRS/QT), SpO₂ + CO-oximetry when relevant
• Activated charcoal within ~1 h for selected agents if the airway is protected; later for anticholinergics/delayed-release — call poison centre

4 · Don’t miss

• Acetaminophen (paracetamol)
  Biggest silent killer. Plot a level drawn ≥4 h post-ingestion on the Rumack-Matthew nomogram (US treatment line 150 µg/mL at 4 h). For a concerning acute overdose, start NAC while awaiting results if testing would delay treatment beyond 8 h. Unknown timing needs the poison-centre pathway, not the nomogram. For repeated supratherapeutic ingestion spanning >24 h, use acetaminophen concentration and AST/ALT to decide NAC; do not use the nomogram. High-risk exposure (≥30 g or above the high-risk nomogram line) requires toxicology advice. Continue NAC until clinical and laboratory stopping criteria are met, not merely until a fixed infusion ends. SNAP 12 h NAC is a UK regimen; US/Canada use their 2023 consensus pathway.
• Opioids
  Pinpoint pupils + respiratory depression → titrate naloxone to ventilation, not wakefulness.
• Tricyclic antidepressants / sodium-channel blockers
  QRS ≥100–110 ms → sodium bicarbonate immediately; anticipate sudden deterioration.
• Salicylates
  Tinnitus, hyperventilation, mixed acid-base picture — alkalinize serum/urine, prepare for hemodialysis.
• Carbon monoxide
  Whole household, headache, normal SpO₂ — CO-oximetry, high-flow O₂ ± hyperbaric per criteria.