Lesson
Treat the Failing System Before Naming the Poison
The exact substance may be unknown while respiratory failure, shock, seizure, hypoglycemia, or hyperthermia is already causing injury. Toxicology begins with resuscitation and a disciplined exposure reconstruction.
- Physiologic stabilization
- Poison center
- Exposure history
- Mixed ingestion
- Intent and safety
Treat ventilation, circulation, seizure, temperature, and reversible metabolic threats.
Resolve product, ingredient, formulation, dose, route, time, intent, and coexposures.
Connect the evolving case to poison-center and medical-toxicology guidance.
Start with physiology
Assess responsiveness, airway protection, respiratory rate and effort, oxygenation, ventilation, perfusion, rhythm, temperature, glucose, and seizure activity. Give standard life support and time-critical empiric therapy when the clinical pattern supports it. An antidote never replaces ventilation, oxygenation, chest compressions, vasopressors, or correction of a lethal metabolic problem.
Reconstruct the exposure
Identify product, active ingredients, concentration, formulation, amount, route, time, intent, and coexposures. Collect containers, photographs, pill counts, pharmacy records, scene details, and collateral history. Account for extended-release products, combination tablets, transdermal systems, and delayed absorption.
Use experts early
Regional poison centers and medical toxicologists provide current, case-specific guidance. Share age, weight, pregnancy status, organ function, symptoms, vital signs, ECG, laboratory data, treatments, and response. Recontact them as the course changes.
Protect the person after stabilization
Intentional poisoning requires suicide-safety precautions, trauma-informed assessment, and a disposition plan that addresses access to medicines or chemicals. Accidental poisoning should trigger storage, packaging, dosing, vision, cognition, and caregiver review.
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Lesson
Reduce Exposure Without Creating a Second Injury
Decontamination is not a ritual. The route, substance, time, airway, gastrointestinal function, expected toxicity, and available evidence determine whether an intervention helps or harms.
- Route-specific first aid
- Button batteries
- Activated charcoal
- Urine alkalinization
- Hemodialysis
Prevent secondary exposure
Stop ongoing absorption
Avoid spreading contamination
Skin, lung, and clothing
Protect rescuers and match irrigation or removal to skin, eye, inhaled, or swallowed toxin.
Use charcoal only when adsorption, timing, bowel function, and airway safety align.
Reserve alkalinization, multidose charcoal, and dialysis for compatible toxins and severity.
Match first aid to the route
Remove contaminated clothing and irrigate skin or eyes according to the substance and expert guidance. Move inhalation victims to fresh air only when rescuers can do so safely. Do not place household chemicals, drops, or neutralizing agents into an exposed eye, ear, nose, or wound unless directed.
Treat button batteries as time critical
An esophageal battery can generate hydroxide and cause severe injury within about two hours. Obtain urgent imaging and remove an esophageal battery immediately. For a child at least 12 months old who can swallow and ingested a possible lithium coin cell within 12 hours, 10 mL of commercial honey every 10 minutes for up to six doses can slow injury while traveling to emergency care. It must not delay imaging or removal.
Use charcoal selectively
Single-dose activated charcoal is not routine. It can be considered after a potentially toxic ingestion of a substance that charcoal adsorbs, especially early, when the airway is intact or protected and aspiration risk is acceptable. It is unsuitable for caustics and poorly adsorbed substances and can be dangerous with obstruction, ileus, or an unprotected airway.
Escalate elimination by mechanism
Urine alkalinization enhances elimination of selected weak acids such as salicylate. Multidose charcoal has narrow toxin-specific roles. Hemodialysis depends on toxicity, clinical trajectory, molecular characteristics, endogenous clearance, and the ability of the procedure to change outcome. Clinical deterioration can justify dialysis before a conventional concentration threshold is reached.
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Lesson
Read the Pattern, Then Challenge It
Toxidromes and targeted tests organize uncertainty. They guide urgent therapy, but mixed ingestions, delayed kinetics, and medical mimics mean the pattern must be revised as new evidence arrives.
- Toxidromes
- Pupils and secretions
- ECG
- Acid-base data
- Targeted testing
Map pupils, moisture, secretions, temperature, bowel activity, tone, reflexes, and clonus.
Separate QRS widening, QT prolongation, conduction block, and ventricular instability.
Read pH, anion gap, osmolar gap, lactate, and toxin levels as moving signals.
Recognize high-yield patterns
Opioid poisoning centers on respiratory depression. Cholinergic poisoning is wet with secretions and can include fasciculations and weakness. Anticholinergic poisoning is hot, dry, mydriatic, delirious, and retentive. Sympathomimetic poisoning is agitated, diaphoretic, hypertensive, and often hyperthermic. Serotonin toxicity features clonus and hyperreflexia in a compatible exposure.
Use the ECG as a toxicology test
Measure QRS, QT, rhythm, rate, and conduction. QRS widening with hypotension after a tricyclic or another sodium-channel blocker is a bicarbonate-responsive emergency. QT prolongation requires drug review, electrolyte correction, and rhythm surveillance but does not imply sodium-channel blockade by itself.
Interpret gaps across time
Anion gap, osmolar gap, pH, bicarbonate, lactate, ketones, and measured osmolality are time-dependent clues. A normal osmolar gap can occur late in toxic alcohol poisoning after the parent alcohol has become a toxic acid. Salicylate toxicity can produce respiratory alkalosis and metabolic acidosis together.
Order tests that change care
Bedside glucose, ECG, metabolic panel, acid-base data, kidney and liver function, pregnancy testing when relevant, and selected acetaminophen, salicylate, alcohol, iron, digoxin, or other levels are more useful than an indiscriminate screen. Routine urine immunoassays miss important agents and can produce false positives.
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Lesson
Interrupt Acetaminophen Injury Before the Liver Declares It
A patient can feel well while toxic metabolism is progressing. The decisive work is accurate exposure classification, correctly timed concentrations, early acetylcysteine, and treatment that continues until stopping criteria are met.
- NAPQI
- Rumack-Matthew nomogram
- Acetylcysteine
- Extended release
- Liver failure
Known-time acute, unknown-time, repeated, delayed, or extended-release ingestion.
Use a concentration at least four hours after a valid known-time acute exposure.
Start early, monitor response, and continue until biochemical and clinical stopping criteria are met.
Connect dose to toxic metabolism
Most acetaminophen is conjugated to nontoxic products. A smaller CYP pathway forms NAPQI, which glutathione normally detoxifies. With sufficient exposure, conjugation and glutathione capacity are overwhelmed, NAPQI binds hepatic proteins, and centrilobular injury can progress to liver failure.
Use the nomogram in its lane
The revised Rumack-Matthew nomogram supports decisions after a known-time acute ingestion using a concentration obtained at least four hours after ingestion. It does not govern an unknown time, repeated supratherapeutic use, staggered exposure, a pre-four-hour concentration, or an unreliable history. Extended-release or delayed-absorption exposures can require repeat concentrations.
Start acetylcysteine safely
Acetylcysteine is most effective when started early, but it can benefit later liver injury. Current intravenous labeling includes two-bag and three-bag options for eligible patients, with weight-specific dilution and fluid precautions. Monitor for hypersensitivity and manage reactions without permanently abandoning a needed antidote when safe resumption is possible.
Stop by criteria, not by clock
At the planned end of treatment, reassess acetaminophen concentration, aminotransferases, INR, clinical status, and other current consensus criteria. Continue treatment when acetaminophen remains detectable, injury is worsening, or recovery criteria are unmet. Massive ingestion, acidosis, coma, delayed absorption, or liver failure needs immediate toxicology and critical care escalation.
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Lesson
Restore Breathing, Then Protect Against Recurrence
Opioid death is a ventilation problem. Naloxone can reverse it temporarily, but rescue breathing, repeat dosing, observation, and emergency care remain essential. Most other sedatives depend on supportive care.
- Respiratory depression
- Naloxone
- Renarcotization
- Flumazenil
- Supportive care
Support oxygenation and ventilation before and during antagonist delivery.
Give promptly and repeat with a new device when response is absent or respiratory depression returns.
The opioid can outlast naloxone, so emergency care and continued observation remain essential.
Recognize the respiratory emergency
Slow, shallow, irregular, or absent breathing with reduced responsiveness is enough to act on suspected opioid exposure. Cyanosis and pinpoint pupils can occur but are not required. Ventilation and oxygenation begin immediately while naloxone is obtained.
Use naloxone as one part of rescue
Give the available formulation promptly and activate emergency care. Current intranasal labeling permits another single-use device every 2 to 3 minutes when the patient does not respond or relapses. Continue rescue breathing or CPR as indicated. Partial agonists can require repeated or higher total exposure under clinical guidance.
Expect recurrence and withdrawal
Many opioids last longer than naloxone, so respiratory depression can return. Continue observation and repeat dosing. Naloxone can precipitate acute withdrawal, but this risk does not justify withholding treatment from life-threatening respiratory depression.
Reserve flumazenil for selected patients
Benzodiazepine and other sedative poisoning is usually treated supportively. Flumazenil can cause seizures or withdrawal in chronic benzodiazepine exposure, seizure disorders, or proconvulsant mixed overdose. It is not a routine coma cocktail and requires careful risk selection.
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Lesson
Treat the Mechanism Behind Poisoned Shock
Bradycardia, wide-complex dysrhythmia, and shock can look similar at the monitor while arising from very different toxic mechanisms. ECG, glucose, perfusion, ventricular function, and exposure history guide therapy.
- Beta blockers
- Calcium-channel blockers
- High-dose insulin
- Digoxin
- Sodium-channel blockade
Use ECG, glucose, perfusion, and ventricular function to identify the dominant failure.
Connect calcium, insulin, Fab, bicarbonate, vasopressors, or other therapy to the toxin.
Mobilize invasive monitoring, toxicology, and extracorporeal support before collapse.
Differentiate beta-blocker and calcium-channel blocker physiology
Both can produce bradycardia, conduction delay, myocardial depression, and shock. Hypoglycemia can accompany selected beta blockers, while hyperglycemia supports severe calcium-channel blocker toxicity. Calcium, glucagon, high-dose insulin, vasopressors, and other therapies are selected from the toxin and hemodynamic phenotype.
Operate high-dose insulin safely
High-dose insulin supports myocardial metabolism and contractility in severe beta-blocker or calcium-channel blocker poisoning. Pair it with dextrose when needed and frequent glucose, potassium, volume, and perfusion monitoring. The monitoring system is part of the treatment.
Neutralize life-threatening digoxin
Digoxin immune Fab is used for life-threatening or potentially life-threatening digitalis toxicity. Dose from the known ingestion or concentration when reliable, but do not delay for perfect data in ventricular dysrhythmia, severe hyperkalemia, or major instability. Total digoxin assays after Fab can be misleading.
Recognize sodium-channel blockade
Tricyclic antidepressants and other membrane-active drugs can widen the QRS, lower blood pressure, trigger seizures, and cause ventricular dysrhythmias. Sodium bicarbonate is directed at the sodium-channel and acidemia problem. Serial ECG and hemodynamic response guide repeated treatment.
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Lesson
Block Toxic Metabolism and Preserve Oxygen Use
Toxic alcohols, cyanide, methemoglobin, and salicylates impair physiology through different chemistry. A gap, color, oxygen value, or concentration is meaningful only when connected to timing and the patient's condition.
- Toxic alcohols
- Fomepizole
- Cyanide
- Methemoglobinemia
- Salicylates
Use fomepizole to stop toxic metabolite formation and dialysis when severity requires.
Give hydroxocobalamin on high clinical suspicion with complete resuscitation.
Confirm the dyshemoglobin pattern and apply methylene-blue safety boundaries.
Stop toxic alcohol metabolism
Fomepizole competitively inhibits alcohol dehydrogenase and limits formation of toxic methanol and ethylene glycol metabolites. Severe acidosis, visual or kidney injury, very high concentrations, or clinical deterioration can require hemodialysis. Osmolar and anion gaps change across the course and cannot exclude exposure alone.
Treat suspected cyanide without delay
Cyanide blocks cellular oxygen utilization and can cause coma, shock, cardiovascular collapse, and severe lactic acidosis, especially after enclosed-space fire exposure. Current hydroxocobalamin labeling directs immediate use when clinical suspicion is high together with oxygen and airway, ventilatory, circulatory, and seizure support.
Recognize dyshemoglobinemia
Acquired methemoglobinemia can cause cyanosis, a saturation gap, chocolate-colored blood, and tissue hypoxia despite adequate arterial oxygen tension. Methylene blue is used for clinically significant disease, but G6PD-related hemolysis risk, serotonergic drug interactions, kidney function, and monitoring interference require attention.
Keep salicylate patients alkalemic
Salicylates can produce tinnitus, vomiting, tachypnea, fever, confusion, pulmonary edema, and a mixed respiratory alkalosis and metabolic acidosis. Give bicarbonate to alkalinize serum and urine, correct potassium, avoid preventable acidemia, and mobilize hemodialysis early for severe clinical toxicity. Chronic poisoning can be dangerous at lower concentrations than acute poisoning.
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Lesson
Separate Wet, Dry, Adrenergic, and Serotonergic Emergencies
Autonomic and neuromuscular findings can rapidly distinguish several dangerous syndromes. The treatment target is the physiology that threatens the airway, brain, temperature, and circulation.
- Organophosphates
- Atropine
- Pralidoxime
- Anticholinergic
- Sympathomimetic and serotonin
Dry secretions with atropine and reverse appropriate organophosphate enzyme inhibition with pralidoxime.
Separate anticholinergic dryness from sympathomimetic sweating, then control heat and agitation.
Use hyperreflexia and clonus to distinguish serotonin toxicity from a medication list alone.
Treat the cholinergic airway
Organophosphate acetylcholinesterase inhibition produces bronchorrhea, bronchospasm, salivation, vomiting, diarrhea, urination, bradycardia or tachycardia, fasciculations, weakness, and respiratory paralysis. Protect staff from contamination. Titrate atropine to improved bronchial secretions and ventilation, not pupil size, and give pralidoxime early for appropriate exposures.
Support anticholinergic delirium
Antimuscarinic poisoning produces hot dry skin, mydriasis, delirium, tachycardia, urinary retention, ileus, and hyperthermia. Use cooling, fluids, benzodiazepines when indicated, bladder care, and ECG evaluation. Physostigmine can be useful in carefully selected pure anticholinergic toxicity but requires expert exclusion of conduction and seizure hazards.
Control sympathomimetic heat and struggle
Cocaine, amphetamines, and related stimulants can cause diaphoresis, severe agitation, hypertension, tachycardia, ischemia, seizures, rhabdomyolysis, and hyperthermia. Benzodiazepines, rapid active cooling, fluids, and targeted cardiovascular treatment reduce adrenergic drive. Prolonged physical struggle can worsen acidosis and heat injury.
Use neuromuscular findings for serotonin
Serotonin toxicity after a compatible exposure features clonus, hyperreflexia, tremor, agitation, autonomic instability, and hyperthermia. Stop serotonergic drugs, give benzodiazepines and supportive care, cool aggressively, and escalate severe disease. A drug list plus fever without the characteristic examination is insufficient.
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Lesson
Match Rescue Therapy to the Broken Biochemical Pathway
Some poisonings are best understood as pathway failures. Dextrose, octreotide, pyridoxine, leucovorin, glucarpidase, and uridine triacetate work only when matched to the right mechanism and timing.
- Hypoglycemia
- Octreotide
- Pyridoxine
- Glucarpidase
- Uridine triacetate
Give dextrose and use octreotide to suppress recurrent sulfonylurea-driven insulin release.
Replace pyridoxine while controlling seizures and acidosis.
Coordinate leucovorin, glucarpidase, or uridine triacetate by mechanism and time window.
Prevent recurrent hypoglycemia
Insulin and secretagogues can produce prolonged or recurrent neuroglycopenia. Give dextrose, nutrition when safe, and frequent glucose monitoring. Octreotide suppresses insulin release and is useful for clinically significant sulfonylurea-induced recurrent hypoglycemia. One normal glucose after a bolus does not establish recovery.
Replace pyridoxine in isoniazid poisoning
Isoniazid depletes functional pyridoxal phosphate and impairs gamma-aminobutyric acid synthesis, causing severe seizures and acidosis. Give intravenous pyridoxine promptly with benzodiazepines and critical support. Use the known dose or an accepted empiric protocol when the ingestion is unknown.
Coordinate methotrexate rescue
Leucovorin bypasses folate antagonism. Glucarpidase enzymatically lowers plasma methotrexate when delayed elimination from impaired kidney function creates toxic concentrations after high-dose therapy. Continue hydration, urine alkalinization, laboratory monitoring, and correctly timed leucovorin because glucarpidase can cleave folates when given too close together.
Recognize the fluoropyrimidine clock
Uridine triacetate is emergency treatment after fluorouracil or capecitabine overdose or selected early-onset severe toxicity. Current labeling emphasizes initiation within 96 hours and a complete 20-dose course. It is not routine treatment for ordinary delayed adverse effects because it can reduce anticancer efficacy.
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Lesson
Make Rare Antidotes Operational Before the Emergency
A lifesaving product is useful only when the team can identify the indication, locate it, prepare it, administer it, monitor it, and replace it. Preparedness also protects medication continuity during disasters.
- Antidote stock
- Preparation
- Envenomation
- Rabies exposure
- Disaster continuity
Match local risk, transfer time, storage, expiry, and replenishment.
Place dosing, mixing, compatibility, monitoring, and consultation at the bedside.
Preserve access to critical medicines during disasters and coordinate envenomation and rabies response.
Build an antidote system
Use risk assessment and regional transfer time to determine stock. Standardize preparation cards, mixing supplies, dosing support, monitoring, storage, and expiry review. Simulate rare high-risk workflows such as hydroxocobalamin, digoxin immune Fab, high-dose insulin, and snake antivenom.
Respond safely to snakebite
For suspected North American pit viper envenomation, remove constricting items, immobilize the limb, transport promptly, and obtain poison-center guidance. Avoid incision, suction, ice, electric shock, and tight tourniquets. Progressive local injury, hematologic toxicity, or systemic effects can require antivenom and serial reassessment.
Use public health for rabies decisions
Wash animal wounds immediately. Species, geography, exposure type, animal testing or observation, and prior vaccination determine postexposure prophylaxis. For an unvaccinated patient with a qualifying exposure, vaccine and human rabies immune globulin are used according to current public-health guidance.
Preserve medication access during disasters
Plan for cold chain, power loss, controlled substances, documentation, alternate dispensing, surge demand, accessible communication, and vulnerable patients. Prioritize continuity for insulin, antiseizure drugs, transplant medicines, anticoagulants, oxygen-related therapies, and other treatments where interruption can rapidly cause harm.
Quick check
Module test
Check the connections.
Each attempt draws 10 questions from the complete 160 question bank.
Each attempt draws a fresh set and rearranges the answer choices.
References
Current clinical foundation.
Lecture material was synthesized with the following contemporary guidance. Verify local policy and current guidance before applying clinical information.
- American Heart Association. Adult and Pediatric Special Circumstances of Resuscitation: Poisoning.
- Dart RC, et al. Management of Acetaminophen Poisoning in the US and Canada: A Consensus Statement.
- American Academy of Clinical Toxicology. Position Statements and Recommendations.
- American College of Medical Toxicology. Management Priorities in Salicylate Toxicity.
- National Capital Poison Center. Button Battery Ingestion Triage and Treatment Guideline.
- DailyMed. Acetadote acetylcysteine injection prescribing information.
- DailyMed. Narcan naloxone nasal spray prescribing information.
- DailyMed. Cyanokit hydroxocobalamin prescribing information.
- DailyMed. ProvayBlue methylene blue prescribing information.
- DailyMed. Fomepizole injection prescribing information.
- DailyMed. Voraxaze glucarpidase prescribing information.
- DailyMed. Vistogard uridine triacetate prescribing information.
- DailyMed. DigiFab digoxin immune Fab prescribing information.