A mechanism-first antidote curriculum: stabilize airway/ventilation/circulation, identify the physiologic poison phenotype, use the antidote that changes that mechanism, and arrange enhanced elimination when the toxin can actually be removed.
Recognize sodium-channel blockade, cardiogenic toxin shock, cholinergic crisis, opioid respiratory depression, toxic alcohols, cyanide and digoxin toxicity.
Use sodium bicarbonate for life-threatening sodium-channel blocker cardiotoxicity and high-dose insulin early for severe beta-blocker/calcium-channel blocker poisoning.
Know the limits of naloxone, fomepizole, NAC, digoxin Fab, atropine/pralidoxime, methylene blue and hydroxocobalamin.
Use poison-center/toxicology consultation and EXTRIP-style dialysis criteria rather than reflex extracorporeal therapy.
Treat the patient and physiologic mechanism—not the reported ingestion dose alone.
The table below is a selection framework. Open the individual monograph for exact dosing, preparation, renal/CRRT/IHD adjustment, interactions and evidence traceability.
ICU role: First-line antidotal physiology for TCA and other life-threatening sodium-channel blocker cardiotoxicity.
Monitor: Serial ECG/QRS, pH, Na/K, hemodynamics.
ICU role: High-dose insulin euglycemia therapy (HIET) for life-threatening beta-blocker/calcium-channel blocker cardiogenic shock; also K shift/DKA under different protocols.
Monitor: Glucose, K, hemodynamics, infusion requirements.
ICU role: Calcium support for calcium-channel blocker toxicity and hyperkalemia stabilization.
Monitor: Ionized Ca, ECG, hemodynamics.
ICU role: Antidote for acetaminophen toxicity and selected acute liver failure contexts.
Monitor: AST/ALT, INR, acetaminophen level, clinical trajectory.
ICU role: Alcohol dehydrogenase inhibitor for methanol/ethylene glycol poisoning.
Monitor: Toxic alcohol level when available, pH/anion gap, renal/visual/neurologic status.
ICU role: Competitive opioid antagonist titrated to restore ventilation.
Monitor: Respiratory rate/ventilation, mental status, recurrence.
ICU role: Muscarinic antagonist for cholinergic poisoning and selected bradycardia.
Monitor: Secretions, oxygenation/ventilation, HR/BP.
ICU role: Acetylcholinesterase reactivator used with atropine in organophosphate poisoning.
Monitor: Weakness, ventilation, cholinergic signs.
ICU role: Specific antibody fragments for life-threatening digoxin toxicity.
Monitor: ECG, K, hemodynamics, renal function.
ICU role: Preferred cyanide antidote in many critical poisoning/fire-smoke contexts.
Monitor: Hemodynamics, lactate trend, clinical response.
ICU role: Methemoglobin reductase cofactor for significant acquired methemoglobinemia; also selected vasoplegia rescue under separate protocols.
Monitor: Co-oximetry, symptoms, interaction/G6PD risk.
ICU role: RyR1-directed therapy for malignant hyperthermia; selected NMS use is individualized and lower-certainty.
Monitor: Temperature, CK/K, renal/hepatic function, recurrence.
ICU role: Core therapy for torsades/long-QT ventricular dysrhythmia, including toxin-related cases.
Monitor: ECG/rhythm, renal function, Mg exposure.
| Agent | ICU role | Why I choose it | Why I hesitate | What I monitor |
|---|---|---|---|---|
| Sodium Bicarbonate Alkalinizing Agent / Buffer | First-line antidotal physiology for TCA and other life-threatening sodium-channel blocker cardiotoxicity. | ✓ QRS widening, ventricular dysrhythmia or hypotension from sodium-channel blockade. | ✕ Avoid indiscriminate alkalinization; watch sodium, pH and potassium. | Serial ECG/QRS, pH, Na/K, hemodynamics. |
| Regular Insulin (IV) Rapid-Onset IV Insulin — Endogenous Peptide Hormone | High-dose insulin euglycemia therapy (HIET) for life-threatening beta-blocker/calcium-channel blocker cardiogenic shock; also K shift/DKA under different protocols. | ✓ Early in severe myocardial dysfunction/toxin shock with expert guidance. | ✕ Requires much higher insulin exposure than hyperkalemia treatment and intensive dextrose/K monitoring. | Glucose, K, hemodynamics, infusion requirements. |
| Calcium Gluconate Electrolyte / Cardiac Membrane Stabilizer | Calcium support for calcium-channel blocker toxicity and hyperkalemia stabilization. | ✓ CCB poisoning with shock/arrhythmia as part of multimodal resuscitation. | ✕ Often temporary/incomplete; do not delay HIET/vasopressors when shock persists. | Ionized Ca, ECG, hemodynamics. |
| N-Acetylcysteine Glutathione precursor / antidote | Antidote for acetaminophen toxicity and selected acute liver failure contexts. | ✓ Start promptly when acetaminophen nomogram/ingestion history or liver injury indicates treatment; late benefit can remain. | ✕ Nomogram is invalid for repeated supratherapeutic/chronic uncertain ingestions; interpret context. | AST/ALT, INR, acetaminophen level, clinical trajectory. |
| Fomepizole Alcohol dehydrogenase inhibitor | Alcohol dehydrogenase inhibitor for methanol/ethylene glycol poisoning. | ✓ Suspected/confirmed toxic alcohol exposure with compatible osmolar/anion-gap or level criteria. | ✕ Does not remove existing toxic metabolites; dialysis may still be required. | Toxic alcohol level when available, pH/anion gap, renal/visual/neurologic status. |
| Naloxone Opioid antagonist | Competitive opioid antagonist titrated to restore ventilation. | ✓ Opioid-induced respiratory depression. | ✕ Goal is adequate ventilation, not necessarily full arousal; short action can be followed by re-sedation and withdrawal. | Respiratory rate/ventilation, mental status, recurrence. |
| Atropine Anticholinergic / Competitive Muscarinic Receptor Antagonist | Muscarinic antagonist for cholinergic poisoning and selected bradycardia. | ✓ Organophosphate/carbamate poisoning—titrate to drying of bronchial secretions/adequate ventilation, not pupil size. | ✕ Large cumulative doses may be required in poisoning; tachycardia alone is not the endpoint. | Secretions, oxygenation/ventilation, HR/BP. |
| Pralidoxime Cholinesterase reactivator | Acetylcholinesterase reactivator used with atropine in organophosphate poisoning. | ✓ Early organophosphate toxicity, especially nicotinic weakness, under toxicology guidance. | ✕ Does not replace atropine for life-threatening muscarinic secretions/bronchospasm. | Weakness, ventilation, cholinergic signs. |
| Digoxin Immune Fab Digoxin-specific antibody fragments | Specific antibody fragments for life-threatening digoxin toxicity. | ✓ Serious dysrhythmia, hyperkalemia/hemodynamic instability or other accepted severe toxicity criteria. | ✕ Post-Fab total digoxin levels are misleading; hypokalemia/heart-failure recurrence can occur. | ECG, K, hemodynamics, renal function. |
| Hydroxocobalamin Cyanide antidote | Preferred cyanide antidote in many critical poisoning/fire-smoke contexts. | ✓ Suspected severe cyanide toxicity—do not wait for confirmatory cyanide levels in an unstable patient. | ✕ Causes red discoloration and can interfere with some laboratory/dialysis optical sensors. | Hemodynamics, lactate trend, clinical response. |
| Methylene Blue Redox agent / guanylate cyclase inhibitor | Methemoglobin reductase cofactor for significant acquired methemoglobinemia; also selected vasoplegia rescue under separate protocols. | ✓ Symptomatic/significant methemoglobinemia when no major contraindication. | ✕ Serotonergic toxicity risk and reduced efficacy/hemolysis concerns in G6PD deficiency; not for sulfhemoglobinemia. | Co-oximetry, symptoms, interaction/G6PD risk. |
| Dantrolene Ryanodine receptor antagonist | RyR1-directed therapy for malignant hyperthermia; selected NMS use is individualized and lower-certainty. | ✓ Malignant hyperthermia with immediate crisis protocol activation. | ✕ Do not teach as mandatory first-line drug for every NMS case. | Temperature, CK/K, renal/hepatic function, recurrence. |
| Magnesium Sulfate Electrolyte / Multi-Mechanism Membrane & Neuromuscular Modulator | Core therapy for torsades/long-QT ventricular dysrhythmia, including toxin-related cases. | ✓ Torsades regardless of baseline magnesium concentration. | ✕ Does not substitute for sodium bicarbonate in sodium-channel blockade or for defibrillation when unstable. | ECG/rhythm, renal function, Mg exposure. |
Why: The immediate problem is fast sodium-channel blockade; bicarbonate increases sodium load and alkalemia to antagonize it.
Why: AHA poisoning guidance recommends high-dose insulin early for life-threatening beta-blocker/CCB poisoning.
Why: The target is reversal of life-threatening muscarinic pulmonary effects.
Why: Toxic metabolites drive injury; fomepizole prevents new metabolite formation while dialysis removes parent alcohol/metabolites when indicated.
Why: Cyanide assays are not timely enough for resuscitation decisions.
Recognition becomes selection, then organ-failure adjustment, competing physiology and senior-level prioritization.
An opioid-exposed patient is somnolent with RR 5/min but has a pulse and BP is stable.
Give naloxone titrated to restore adequate ventilation and airway protection. Full agitation/withdrawal is not the therapeutic goal.
Nortriptyline overdose, seizure resolved, BP 80/45 and QRS 146 ms.
Treat sodium-channel blockade immediately with sodium bicarbonate while supporting airway/ventilation and shock. Do not wait for a serum TCA level.
Massive verapamil ingestion with bradycardia, EF 20%, lactate 7 and escalating norepinephrine.
Use multimodal toxicologic shock therapy—calcium plus early HIET and appropriately selected vasoactive support, with toxicology consultation and consideration of mechanical support if refractory.
Severe high-anion-gap acidosis, osmolar gap and visual complaints after uncertain ingestion; send-out methanol level will take 8 hours.
Start fomepizole based on the clinical probability and arrange dialysis evaluation now. The antidote blocks further toxic metabolite formation; it does not reverse existing severe acidosis/organ toxicity by itself.
Coma, shock, QRS 180 ms, terminal R in aVR, severe acidosis, no reliable history. The monitor shows recurrent wide-complex tachycardia.
Treat the physiology as life-threatening sodium-channel blockade: airway/ventilation, repeated bicarbonate strategy, seizure control and hemodynamic support. Avoid sodium-channel-blocking antiarrhythmics; use toxicology guidance for lidocaine/vasopressor/ECMO escalation if refractory.
A deliberately narrow-role buffer reserved for severe metabolic acidosis with concurrent AKI, sodium-channel-blocker toxicity, and select hyperkalemia with significant concurrent acidemia — explicitly NOT a routine therapy for la…
IV regular insulin is used for distinct ICU purposes — DKA, HHS/mixed hyperglycemic crisis, temporizing potassium shift in hyperkalemia, and general ICU glycemic control — each with different dosing and endpoints; insulin SHIFTS …
First-line cardiac membrane stabilizer for hyperkalemic ECG changes and definitive replacement therapy for symptomatic hypocalcemia — the single most important teaching point is that it stabilizes the myocardium without changing …
Specific antidote for acetaminophen poisoning and an important therapy in selected non-acetaminophen acute liver failure contexts.
First-line antidote for methanol and ethylene glycol poisoning; dosing changes during prolonged therapy and extracorporeal treatment.
Competitive opioid antagonist used to reverse clinically important opioid-induced respiratory/CNS depression while minimizing severe withdrawal.
Competitive muscarinic antagonist that blocks vagal parasympathetic tone at the SA and AV nodes, used as first-line for acute symptomatic sinus bradycardia (1 mg IV push q3–5m, max 3 mg) and in megadoses for organophosphate/choli…
Oxime used with atropine in life-threatening organophosphate poisoning to reactivate phosphorylated acetylcholinesterase before aging. The 2025 AHA guideline considers pralidoxime reasonable for adults and children with life-thre…
Specific antidote for life-threatening digoxin toxicity, especially malignant dysrhythmia, severe hyperkalemia or hemodynamic instability attributable to digoxin.
Cyanide-binding antidote used in suspected severe cyanide poisoning; off-label vasoplegia rescue evidence is much weaker.
Used for acquired methemoglobinemia and off-label rescue of refractory vasoplegia; indications and dosing are completely different.
Specific therapy for malignant hyperthermia; reduces skeletal-muscle calcium release and hypermetabolism.
Spans four genuinely distinct ICU indications — torsades de pointes, adjunctive severe asthma therapy, eclampsia/severe preeclampsia, and simple hypomagnesemia repletion — each with its own mechanism-relevant dosing; no single do…
This Masterclass teaches selection and reasoning. Exact dosing, concentration, infusion preparation, renal/hepatic/RRT adjustment and monitoring must be checked in the linked medication monograph and the institution's current formulary/protocol. Local resistance patterns and regulatory drug availability can change faster than a static teaching page.