Poisoning: general principles and initial management

Manage now— do this, in order

• Treat the patient, not the poison: airway protection and assisted ventilation are the most important treatment measures for any poisoned patient, and most people recover uneventfully on supportive care alone. Intubate for loss of the cough or gag reflex, or GCS 8 or less — respiratory failure is the commonest cause of death in the comatose poisoned patient and comes on abruptly; in many severely poisoned patients reflexes are depressed enough to permit intubation without sedatives or relaxants.Doctor / NurseNot available at your setup — Endotracheal intubation kit, Mechanical ventilator. Where intubation is unavailable, maintain the airway by position, suction and an oropharyngeal airway, and ventilate with a bag-valve-mask while arranging transfer.
• High-flow oxygen while airway and breathing are assessed — and remember it is a genuine antidote in carbon monoxide, cyanide and hydrogen sulphide poisoning (100% by tight-fitting non-rebreathing mask). Establish intravenous access and cardiac monitoring in any potentially serious ingestion, even if the patient looks well.
• Give glucose empirically unless a point-of-care test has excluded hypoglycaemia — adult 50% dextrose 50–100 mL IV, or the same 25 g as 20% dextrose 100 mL or 10% dextrose 250 mL; child 10% dextrose 2 mL/kg IV or IO, and 50% dextrose must never be given to a child; recheck at 10 minutes. Thiamine 100 mg intramuscularly or by slow intravenous injection before the dextrose or in the same infusion in alcohol use disorder, malnutrition or chronic illness — but it must never delay treatment of documented hypoglycaemia.Doctor / Nurse
• Naloxone for a respiratory rate below 8/min, cyanosis or unresponsiveness — adult 0.4–2 mg IV repeated every 2–3 minutes, escalating to 5–10 mg for potent synthetics such as fentanyl; without venous access 0.4–2 mg IM or 2–4 mg intranasally; child 0.01 mg/kg IV/IO, and if there is no response 0.1 mg/kg. Titrate naloxone to a respiratory rate of about 12, not to full consciousness, and never let it delay intubation if that is what the patient needs.Doctor / Nurse
• Hypotension — isotonic crystalloid in 200 mL boluses to a total of 1–2 L, reassessing after each (child 10–20 mL/kg boluses); much larger volumes may be needed in profound depletion. If volume replacement fails, noradrenaline 4–8 micrograms/min intravenously, titrated — more effective than dopamine in tricyclic overdose. Toxin-specific hypotension has specific therapy: sodium-channel blocker — sodium bicarbonate 50–100 mmol IV bolus; beta-blocker — glucagon 5–10 mg IV then 1–5 mg/hour; calcium channel blocker — calcium chloride 1–2 g IV repeated (cumulative 5–10 g and more have been given); either — high-dose insulin euglycaemic therapy 0.5–1 unit/kg/hour IV with glucose supplementation and potassium monitoring.Doctor / NurseNot available at your setup — Infusion pump.
• Seizures — adult lorazepam 2–4 mg IV slowly or diazepam 5–10 mg IV (up to diazepam 10–20 mg or lorazepam 4 mg for persistent fits), or midazolam 5–10 mg IM without venous access, repeated once after 5 minutes; child lorazepam 0.1 mg/kg IV to a maximum of 4 mg, or diazepam 0.3 mg/kg IV or 0.5 mg/kg rectally, or buccal midazolam 0.3 mg/kg. Second line, adult and child: phenobarbital 15–20 mg/kg by slow intravenous infusion at no more than 100 mg/min over not less than 30 minutes. Phenytoin is contraindicated in toxicological seizures — outcomes are worse after loading, particularly in theophylline overdose, and it is specifically contraindicated with sodium-channel-blocking drugs.Doctor / Nurse
• Ventricular arrhythmia of suspected toxicological cause — sodium bicarbonate 50–100 mmol IV by bolus first, and for torsades de pointes with a long QT, magnesium sulphate 2 g IV over 1–2 minutes or overdrive pacing. Hypertension — sedate first: lorazepam 2–3 mg IV often suffices; if it persists give phentolamine 2–5 mg IV, glyceryl trinitrate 1–2 mg/hour by infusion to a maximum of 12 mg/hour, or sodium nitroprusside 0.25–8 micrograms/kg/min. A beta-blocker must never be given alone in stimulant poisoning — unopposed alpha stimulation may paradoxically worsen hypertension and vasospasm, and in tricyclic poisoning class Ia, Ic and III (amiodarone) antiarrhythmics are contraindicated.Doctor / Nurse
• Hyperthermia above 40–41°C — spray the skin with tepid water and fan at high volume, or immerse in an ice-water bath, sedating with diazepam; applying ice to selected surfaces is inadequate cooling. If the rectal temperature is not normal within 20–30 minutes, or there is significant rigidity, paralyse with a non-depolarising agent, then intubate, ventilate and sedate. Arrhythmia, hypotension and hyperthermia will not respond to any drug until hypoxia, acidosis, electrolyte disturbance (especially hypokalaemia) and temperature abnormality have been corrected, and hypotension will not reverse until a temperature below 35°C is normalised — never make a prognostic statement about a cold patient.Doctor / Nurse
• Decontaminate the skin and eyes — remove all clothing and wash with copious lukewarm water or 0.9% saline including behind the ears, under the nails and in skin folds, using a triple wash (water, soap, water) for pesticides and oily substances; irrigate each eye for at least 15 minutes or until it has received at least 1 litre. Activated charcoal only when it is worth it: 50 g orally for an adult, 1 g/kg for a child, ideally within 1 hour of an adsorbable poison, with possible value up to about 6 hours after a sustained-release preparation. Never give charcoal to a comatose or convulsing patient unless it is delivered by gastric tube with the airway protected by a cuffed endotracheal tube, never in ileus, obstruction or after a corrosive, and never add sorbitol or any other cathartic; charcoal does not bind iron, lithium, potassium, sodium, mineral acids, alkalis, ethanol, ethylene glycol, methanol, mercury or petroleum distillates. Syrup of ipecacuanha has no role whatever. Observe asymptomatic or mildly symptomatic patients for at least 4–6 hours from the time of ingestion, and give an antidote only with reasonable certainty of the diagnosis.