Comprehensive guide to assessment, management, and antidotes for toxicological emergencies
Poisoning is the administration of a substance, taken internally or externally, that is injurious to health or dangerous to life. A poison may be a drug, household product, industrial chemical, or plant or animal derivative. The most common route of poisoning is by ingestion, but poisoning by inhalation, injection, skin/eye contamination, or bites may also occur. Poisoning may be accidental or intentional.
Where someone is exposed to a poison by an accidental action and develops symptoms. Poisoning is usually accidental in children under 5, and most commonly due to the exploratory ingestion of a substance found at home.
Part of the spectrum of deliberate self-harm. This encompasses both deliberate self-poisoning and deliberate self-injury.
Use of a quantity of drug in excess of its intended or prescribed dose, and is a major cause of poisoning. It may be accidental or deliberate.
| Drug | Symptoms and Signs |
|---|---|
| Paracetamol | Frequently asymptomatic, nausea and vomiting (usually settle within 24 hours). Continued symptoms suggest hepatic necrosis. |
| Aspirin | Hyperventilation, tinnitus, deafness, vasodilatation, sweating, coma |
| Tricyclic antidepressants | Dry mouth, seizures, coma, cardiac conduction defects, arrhythmias, hypothermia, hypotension |
| SSRIs | Nausea, vomiting, agitation, tremor, nystagmus, drowsiness, sinus tachycardia, seizures, serotonin syndrome |
| Beta-blockers | Lightheadedness, syncope, bradycardia, hypotension; sotalol can cause ventricular tachycardia |
| Calcium-channel blockers | Nausea, vomiting, agitation, confusion, dizziness, coma, hyperglycaemia; verapamil/diltiazem cause arrhythmias |
| Opioids | Drowsiness, coma, respiratory depression, pinpoint pupils |
| Benzodiazepines | Drowsiness, dysarthria, ataxia, nystagmus, respiratory depression, coma |
| Cocaine | Agitation, hypertension, tachycardia, dilated pupils, hallucinations, hyperthermia |
Note: This is not an exhaustive list. Always consult TOXBASE or NPIS for specific management guidance.
| Toxidrome | Common Agents | Signs and Symptoms |
|---|---|---|
| Anticholinergic | Antihistamines, tricyclic antidepressants, carbamazepine | Tachycardia, hyperthermia, dilated pupils, warm and dry skin, urinary retention, agitation |
| Cholinergic | Organophosphates, carbamates, some mushrooms | Salivation, lacrimation, urination, diarrhoea, bronchorrhoea, bronchospasm, bradycardia |
| Opioid | Morphine, codeine, methadone, heroin | Hypoventilation, hypotension, pinpoint pupils, sedation, bradycardia |
| Sympathomimetic | Amphetamines, cocaine, MDMA | Tachycardia, hypertension, dilated pupils, agitation, seizures, hyperthermia, sweating |
| Sedative/hypnotic | Benzodiazepines, ethanol, barbiturates | Ataxia, blurred vision, sedation, hallucinations, slurred speech, nystagmus |
Mnemonic for Anticholinergic: "Hot as a hare, blind as a bat, dry as a bone, red as a beet, mad as a hatter"
Mnemonic for Cholinergic: SLUDGE - Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis
1 The single most important step is prompt removal of clothing (within 15-20 minutes following exposure)
2 Conducted by the casualty themselves if possible
3 Double bag and label all contaminated materials
1 Default for non-caustic chemicals
2 Use dry absorptive materials to blot exposed skin
3 Start at face/head/neck and move downward
1 For caustic/corrosive substances or biological/radiological contaminants
2 Use warm water with 0.5% detergent solution
3 Limit showers to 45-90 seconds
Activated Charcoal: 50g orally in adults if within 1 hour of ingestion. Contraindicated if airway not protected or intestinal obstruction.
For: Opioid poisoning
Dose: 0.4-2mg IV, repeat as needed
For: Paracetamol overdose
Dose: IV regimen over 21 hours
For: Benzodiazepine overdose
Caution: Risk of seizures in mixed overdoses
For: Organophosphate poisoning
Dose: 2mg IV, repeat until drying of secretions
For: Digoxin toxicity
Dose: Varies based on digoxin level
For: Beta-blocker and calcium channel blocker overdose
Dose: 50-150 mcg/kg IV
Important: Always consult TOXBASE or NPIS for specific dosing and administration guidelines for antidotes.