This section outlines the antidote of various high-yield / common poisoning.
 

Poison	Features	Treatment
Methaemoglobinaemia		Methylene blue (methylthioninium chloride)
Aspirin	Main features: Hyperventilation Tinnitus Deafness Sweating Flushing, dizziness (from vasodilatation)	Consider oral activated charcoal (if within 1 hour of ingestion) Management: 1st line: IV sodium bicarbonate (urinary alkalinisation) + replace fluid losses Ensure to correct hypokalaemia before giving sodium bicarbonate   Severe poisoningConsider if - Sodium bicarbonate failed - Plasma salicylate concentration >700 mg/L / 5.1 mmol/L - Severe metabolic acidosis: haemodialysis
Opioids (e.g. morphine, oxycodone, fentanyl)	Classic triad of: Respiratory depression Bilateral miosis Reduced level of consciousness	1st line: naloxone (rapid 400 mcg IV bolus) Intranasal route is an option when no IV access is available If refractory to naloxone, consider benzodiazepine poisoning, as both can present similarly.
Paracetamol	Early features: nausea and vomiting (usually settle within 24 hours) Liver damage is indicated by: RUQ pain and tenderness (maximal 3-4 days after the overdose)	N-acetylcysteine See this article for guidance on when to use N-acetylcysteine.
SSRIs	Nausea and vomiting Agitation Tremor Nystagmus Drowsiness Sinus tachycardia Convulsions	Supportive management: Consider oral activated charcoal (if within 1 hour of ingestion) Treat convulsions with benzodiazepines
Benzodiazepine	Main features: Drowsiness Ataxia Dysarthria Nystagmus Respiratory depression (not always)	Consider oral activated charcoal (if within 1 hour of ingestion) Consider flumazenil only under specialist advice Can be hazardous, esp. in mixed overdoses involving TCAs or in benzodiazepine-dependent patients May inhibit respiration (esp. in those with severe respiratory disorders)
Beta blocker	Cardiac features (primary): Bradycardia - most common Hypotension Syncope Conduction abnormalities Heart failure Other features: Respiratory depression, bronchospasm CNS effects - drowsiness, confusion, convulsions, hallucinations)	Consider oral activated charcoal (if within 1 hour of ingestion) Management: Fluid resuscitation Symptomatic bradycardia → atropine Severe hypotension / heart failure / cardiogenic shock → consider IV glucagon
Calcium channel blocker	Nausea and vomiting Dizziness Agitation Confusion	Consider oral activated charcoal (if within 1 hour of ingestion) Consider: Calcium chloride or gluconate Treat symptomatic bradycardia with atropine
Iron salts	Nausea and vomiting Abdominal pain Diarrhoea Haematemesis Rectal bleeding	Desferrioxamine
Lithium		Supportive treatment - correct dehydration and electrolyte balance   If serum lithium concentration >2 mmol/L + neurological symptoms or renal failure  →haemodialysis
Cocaine	Agitation Mydriasis Tachycardia Hypertension Hallucinations Hyperthermia Hyerptonia Hyperreflexia Chest pain Arrhyhtmias	Diazepam to control agitation Cooling measures to manage hyperthermia
Ecstasy		Diazepam to control agitation
Ethylene glycol and methanol		1st line: fomepizole 2nd line: ethanol (IV or by mouth)
Carbon monoxide		100% high-flow oxygen
Organophosphorus insecticides		1st line: atropine Adjunct: pralidoxime chloride

 

NICE BNF Treatment summaries Poisoning, emergency treatment

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