ICU · Pharmacology
Toxicology Antidotes — ICU
Also known as Antidotes · Naloxone · N-acetylcysteine · Flumazenil · Digoxin Fab · Fomepizole · Methylene blue · Hydroxocobalamin · Lipid emulsion · High-dose insulin euglycaemia therapy · Atropine + pralidoxime · Sodium bicarbonate · Deferoxamine · Succimer · Folinic acid · Andexanet alfa · Idarucizumab · Protamine · Vitamin K · Prothrombin complex concentrate
ICU toxicology antidotes organised by toxin: naloxone (opioids), flumazenil (benzodiazepines - caution seizures), N-acetylcysteine (paracetamol - nomogram-driven), digoxin Fab (life-threatening digoxin toxicity), atropine + pralidoxime (organophosphates - before aging), fomepizole/ethanol (methanol/ethylene glycol - alcohol dehydrogenase inhibition), sodium bicarbonate (TCA Na-channel blockade + salicylate urine alkalinisation), methylene blue (methaemoglobinaemia - NOT G6PD), hydroxocobalamin/sodium thiosulfate/dicobalt EDTA (cyanide), calcium + high-dose insulin euglycaemia therapy + lipid emulsion (CCB/BB), octreotide (sulfonylurea), deferoxamine (iron), succimer/EDTA/BAL (lead), folinic acid/leucovorin (methotrexate), vitamin K/PCC/andexanet/idarucizumab (warfarin and DOAC reversal), protamine (heparin), oxygen/hyperbaric (carbon monoxide). Lipid rescue therapy for lipophilic drug overdose.
Checked against its sources on 1 Sept 2026
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Red flags
- Flumazenil precipitates seizures — avoid in mixed overdose (especially TCA co-ingestion) and chronic benzodiazepine users
- NAC anaphylactoid reaction common in first 2 h (rate-related) — slow/stop infusion, give antihistamine, restart at half rate; non-IgE mediated so does NOT contraindicate completion
- Methylene blue causes haemolysis in G6PD deficiency — screen before giving if possible; alternative is ascorbic acid or exchange transfusion
- Sodium bicarbonate is the antidote for BOTH TCA cardiotoxicity (Na-channel blockade — wide QRS) AND salicylate poisoning (urine alkalinisation) — but the TARGETS differ (blood pH 7.50 for TCA vs urine pH >7.5 for salicylate)
- Hydroxocobalamin turns skin, urine, plasma red-orange for days — not a side effect to chase; also interferes with co-oximetry and many lab assays (carboxyhaemoglobin, liver function)
- Pralidoxime must be given BEFORE the organophosphate AGES (irreversibly binds AChE) — dimethyl compounds age in minutes, diethyl in hours
- Andexanet alfa carries a 24-h restriction window vs PCC which is immediate — andexanet causes heparin-resistant anticoagulation monitoring (elevated anti-Xa is spurious)
- Lipid emulsion can cause ARDS, pancreatitis, fat overload — not a benign rescue; reserve for refractory lipophilic overdose
Meet the patient
A 19-year-old lands in resus at 3am, GCS 8, empty blister packs of paracetamol spilling from her pockets and the time of the last dose uncertain. She is somewhere around eight hours into a staggered overdose, and the question that decides her next hour is the one that decides every tox case: which antidote, and is the clock already too late for decontamination.[1]
Hold those two questions — the antidote and the clock — and the whole topic slots into place beneath them.[1]
References55ShowHide
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