Guide — Emergency Nursing
Toxicology for Nurses Guide
Toxidrome recognition, specific antidotes, opioid overdose, acetaminophen toxicity, and nursing priorities for emergency toxicology — essential content for NCLEX and bedside care.
10 min read · Emergency Nursing
Educational use only. Always contact Poison Control (1-800-222-1222 in the US) for toxicology emergencies. Management is individualized to toxin, ingestion amount, and clinical condition. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Toxidrome Framework
Toxidrome = a constellation of clinical signs and symptoms that characterize poisoning by a class of substances. Recognizing the toxidrome guides empiric treatment while awaiting lab confirmation.
Key assessment: Vital signs + Pupils + Mental status + Skin (wet vs dry) + Bowel sounds — these five components differentiate most toxidromes.
Toxidromes
Opioid Toxidrome
Agents: Heroin, morphine, oxycodone, fentanyl, methadone, tramadol
| Vital signs | Bradycardia, hypotension, hypothermia, bradypnea → apnea |
| Pupils | Miosis (pinpoint pupils) — hallmark |
| Mental status | CNS depression, sedation → coma |
| Other findings | Respiratory depression is the life-threatening feature. Bowel sounds decreased. Fentanyl/synthetic opioids may have minimal pupil change. |
| Antidote | Naloxone (Narcan) 0.4–2 mg IV/IM/IN; repeat q2-3 min; infusion for long-acting opioids |
| Nursing Priority | Respiratory support is priority — BVM if apneic. Naloxone titrate to respirations (not consciousness — avoid precipitating acute withdrawal). Observe for re-sedation (naloxone shorter acting than many opioids). |
Anticholinergic Toxidrome
Agents: Antihistamines (diphenhydramine), TCA antidepressants, atropine, scopolamine, antipsychotics, jimsonweed/belladonna, some mushrooms
| Vital signs | Tachycardia, hypertension, hyperthermia |
| Pupils | Mydriasis (dilated pupils) — hallmark |
| Mental status | Agitation, delirium, hallucinations (classically visual), 'mad as a hatter' |
| Other findings | Classic mnemonic: 'hot as Hades, blind as a bat, dry as a bone, red as a beet, mad as a hatter, full as a flask (urinary retention), fast as a fiddle (tachycardia)'. Skin: hot, dry, flushed. Absent bowel sounds. Urinary retention. |
| Antidote | Physostigmine (specific, for pure anticholinergic toxicity — NOT for TCA OD); benzodiazepines for agitation; avoid physostigmine in TCA toxicity (can cause seizures and asystole) |
| Nursing Priority | Cooling measures for hyperthermia. Foley for urinary retention. Benzos for agitation and seizures. Continuous cardiac monitoring (TCA causes QRS widening, dysrhythmias). Quiet, low-stimulation environment. |
Cholinergic (Organophosphate/Nerve Agent) Toxidrome
Agents: Organophosphate pesticides (malathion, parathion), nerve agents (sarin, VX), some mushrooms (muscarinic), carbamate pesticides
| Vital signs | Bradycardia, hypotension, bronchospasm → respiratory failure |
| Pupils | Miosis (constricted) — hallmark |
| Mental status | Anxiety → seizures → coma |
| Other findings | SLUDGE: Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis. Also: Bronchospasm, Bradycardia, diaphoresis. 'Wet' toxidrome — everything secreting. |
| Antidote | Atropine (large doses — titrate to dry secretions, not heart rate); Pralidoxime (2-PAM) reactivates acetylcholinesterase — must give EARLY before 'aging' of enzyme occurs |
| Nursing Priority | HAZMAT/decontamination first (remove clothing, water irrigation) before touching patient. PPE essential — absorbs through skin. Atropine doses may be enormous. Benzodiazepines for seizures. |
Sympathomimetic Toxidrome
Agents: Cocaine, amphetamines, methamphetamine, MDMA (ecstasy), ephedrine, pseudoephedrine, caffeine (massive doses)
| Vital signs | Tachycardia, hypertension, hyperthermia, tachypnea |
| Pupils | Mydriasis (dilated pupils) |
| Mental status | Agitation, paranoia, hallucinations, psychosis, seizures |
| Other findings | Diaphoresis (wet, unlike anticholinergic). Rhabdomyolysis from hyperthermia/seizures. Cocaine: coronary vasospasm → STEMI possible even in young patients. MDMA: hyponatremia (excessive water drinking). |
| Antidote | No specific antidote. Benzodiazepines for agitation, hypertension, and seizures (first-line). Cooling for hyperthermia. Beta-blockers AVOIDED in cocaine toxicity (unopposed alpha → hypertensive crisis). |
| Nursing Priority | Benzodiazepines are the cornerstone of sympathomimetic toxicity management. Monitor for rhabdomyolysis (CK, urine myoglobin, urine output). 12-lead ECG for chest pain (cocaine MI). Quiet, low-stimulation environment. |
Sedative-Hypnotic Toxidrome
Agents: Benzodiazepines (diazepam, lorazepam), barbiturates, zolpidem, alcohol (ethanol), GHB
| Vital signs | Bradycardia, hypotension, hypothermia, bradypnea |
| Pupils | Miosis or mid-position (variable — pupils less distinctive than opioid) |
| Mental status | Sedation, slurred speech, ataxia, confusion → coma |
| Other findings | Less pronounced respiratory depression than opioids (benzodiazepines alone rarely cause fatal respiratory depression — dangerous when combined with opioids). Alcohol: hypoglycemia risk. Barbiturates: more dangerous CNS depression. |
| Antidote | Flumazenil (reverses benzodiazepines ONLY — NOT alcohol, barbiturates, or other sedatives). CAUTION: may precipitate acute benzodiazepine withdrawal seizures in dependent patients; avoid in TCA or cocaine co-ingestion. |
| Nursing Priority | Supportive care: airway management, aspiration precautions. Monitor blood glucose (especially alcohol). Flumazenil short-acting — re-sedation can occur. Monitor for withdrawal if chronic use. |
Acetaminophen Toxicity — High-Yield
Why it matters: Most common intentional overdose seen in emergency departments. Potentially fatal — causes fulminant hepatic failure 3–4 days after ingestion if untreated. Patient may appear well in Stage 1.
| Stage | Timing | Clinical Features |
|---|---|---|
| Stage 1 | 0–24 hours | N/V, malaise, pallor — patient may appear mildly unwell or completely asymptomatic |
| Stage 2 | 24–72 hours | RUQ pain, LFTs beginning to rise, PT/INR elevating — apparent clinical improvement (deceptive) |
| Stage 3 | 72–96 hours | Peak hepatotoxicity — markedly elevated AST/ALT, coagulopathy, jaundice, encephalopathy, acute renal failure. Fulminant hepatic failure risk. |
| Stage 4 | 4 days – 2 weeks | Recovery (if survived Stage 3 without liver transplant) |
NAC (N-Acetylcysteine) Treatment
- Most effective within 8–10 hours of ingestion
- Use the Rumack-Matthew nomogram: plot serum APAP level vs time since ingestion to determine NAC need
- IV NAC given if patient vomiting or clinical instability; oral if tolerating
- Continue NAC until APAP level undetectable, LFTs improving, and INR normalizing
- NAC given even > 24h in fulminant hepatic failure — still reduces mortality
Key Antidotes Quick Reference
| Toxin / Overdose | Antidote | Notes |
|---|---|---|
| Opioids (heroin, morphine, fentanyl) | Naloxone (Narcan) | 0.4–2 mg IV/IM/IN; repeat q2-3 min |
| Benzodiazepines | Flumazenil (Romazicon) | 0.2 mg IV q1 min, up to 1 mg — caution in seizure-prone patients |
| Acetaminophen | N-acetylcysteine (NAC, Mucomyst) | IV or oral protocol; give within 8–10h of ingestion for best effect |
| Beta-blockers (severe) | Glucagon + high-dose insulin + calcium | Glucagon 1–5 mg IV; high-dose insulin euglycemia therapy |
| Calcium channel blockers (severe) | Calcium (gluconate or chloride) + high-dose insulin | Calcium gluconate 1–3g IV; insulin 1 unit/kg bolus + infusion |
| Tricyclic antidepressants (TCA) | Sodium bicarbonate | 1–2 mEq/kg IV bolus — alkalinizes plasma, reverses Na channel blockade; target pH 7.45–7.55 |
| Organophosphates (nerve agents) | Atropine + Pralidoxime (2-PAM) | Atropine 2–4 mg IV (titrate to dry secretions); pralidoxime 1–2g IV over 15–30 min |
| Digoxin toxicity | Digoxin-specific antibody fragments (Digibind, DigiFab) | Calculated based on serum dig level or number of pills ingested |
| Carbon monoxide | 100% O₂ (hyperbaric for severe cases) | 100% O₂ via NRB reduces CO half-life to 60–90 min (vs 4–5h on room air) |
| Methanol / ethylene glycol | Fomepizole (preferred) or ethanol | Fomepizole 15 mg/kg IV loading dose; blocks alcohol dehydrogenase |
| Iron overdose | Deferoxamine (chelation) | IV infusion; used for symptomatic iron toxicity or serum iron > 500 mcg/dL |
| Lead poisoning | DMSA (succimer, oral chelation) or EDTA (IV for encephalopathy) | DMSA 10 mg/kg q8h for 5 days, then q12h |
| Heparin overdose | Protamine sulfate | 1 mg per 100 units of heparin given in last 2–2.5h |
| Warfarin overdose | Vitamin K + 4-factor PCC (Kcentra) or FFP for urgent reversal | Vitamin K 2.5–10 mg IV/PO; PCC 25–50 units/kg for urgent reversal |
General Overdose Nursing Priorities
| ABCs first | Airway, Breathing, Circulation — stabilize before focused management |
| Identify the toxin | History (witness, family, pill bottles, empty bags), toxidrome pattern, serum/urine toxicology screen. Call Poison Control early. |
| IV access × 2 | Two large-bore IVs for all serious overdoses |
| Cardiac monitoring | 12-lead ECG + continuous telemetry — QRS widening (TCA, Na channel blockers), QTc prolongation (antipsychotics, antiarrhythmics, methadone), bradydysrhythmias (opioids, beta-blockers) |
| Glucose | Check glucose immediately (altered mental status may be hypoglycemia) |
| Decontamination | Activated charcoal within 1–2h of ingestion if alert and able to protect airway; NOT for caustics, hydrocarbons, metals. Whole bowel irrigation for sustained-release medications, iron, lead. |
| Psychiatric evaluation | Intentional overdose requires psychiatric evaluation before discharge. Safe environment, remove sharps/medications from room. |
NCLEX Pearls
Opioid: miosis + bradypnea + coma = naloxone. Titrate to respirations, not consciousness. Observe for re-sedation.
Anticholinergic mnemonic: hot, blind, dry, red, mad, full, fast. Physostigmine is the antidote — NOT for TCA (causes seizures/asystole).
Organophosphate = SLUDGE (all secretions increased). Atropine (dries secretions) + 2-PAM (early). HAZMAT decontamination first.
Sympathomimetic: benzos are first-line for agitation, hypertension, and seizures. Avoid beta-blockers with cocaine (unopposed alpha → hypertensive crisis).
Flumazenil reverses benzodiazepines ONLY — NOT alcohol or other CNS depressants. Can precipitate seizures in benzo-dependent patients.
Acetaminophen overdose: Stage 1 appears benign. Give NAC within 8–10h. Use Rumack-Matthew nomogram. LFTs peak at 72–96h.
TCA overdose = sodium bicarb (alkalinize plasma, reverse Na channel blockade). QRS widening is the dangerous sign.
Related Resources
Standards & sources
Fact-checked Jun 20, 2026This page is written to align with Emergency Nurses Association (ENA) · AHA ACLS / PALS Guidelines · Advanced Trauma Life Support (ATLS). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →