Overdose And Exposure Management - NAPLEX
- Which antidote is used for acetaminophen overdose to prevent hepatic injury?
- N-acetylcysteine (NAC). Replenishes glutathione to neutralize the hepatotoxic metabolite NAPQI in acetaminophen overdose.
- Which antidote is used for digoxin toxicity with life-threatening arrhythmias or hyperkalemia?
- Digoxin immune Fab. Binds free digoxin to form complexes that are rapidly excreted, reversing cardiac toxicity.
- Which antidote is used for life-threatening bleeding from dabigatran?
- Idarucizumab. Specifically binds dabigatran as a monoclonal antibody to neutralize its anticoagulant activity.
- What complication can occur after naloxone in opioid-dependent patients?
- Acute opioid withdrawal. Rapid opioid receptor displacement in dependent individuals precipitates symptoms like agitation and vomiting.
- What is the first-line antidote for suspected opioid overdose with respiratory depression?
- Naloxone. Competitively antagonizes mu-opioid receptors to rapidly reverse respiratory depression in opioid toxicity.
- What is the goal of naloxone titration in opioid overdose management?
- Restore adequate ventilation, not full arousal. Prioritizes reversing life-threatening respiratory depression while avoiding precipitation of severe withdrawal.
- Which antidote is used for cyanide poisoning from smoke inhalation or industrial exposure?
- Hydroxocobalamin. Chelates cyanide ions to form nontoxic cyanocobalamin for urinary excretion.
- What is the preferred initial naloxone route for a layperson in the community setting?
- Intranasal naloxone. Offers rapid absorption and user-friendly administration without needles, ideal for non-professionals.
- Which agent is used for iron overdose to bind free iron and enhance elimination?
- Deferoxamine. Chelates excess serum iron to form ferrioxamine, facilitating renal elimination and reducing toxicity.
- Which antidote is used for benzodiazepine overdose when reversal is clearly indicated?
- Flumazenil. Acts as a competitive antagonist at GABA_A receptors to reverse benzodiazepine-induced sedation.
- Which antidote is used for symptomatic beta-blocker overdose with bradycardia or hypotension?
- Glucagon. Stimulates cardiac adenylate cyclase independently of beta-receptors to improve hemodynamics.
- Which medication is used to prevent recurrent hypoglycemia after sulfonylurea overdose?
- Octreotide. Suppresses insulin release from beta cells to mitigate prolonged hypoglycemic effects of sulfonylureas.
- What is the primary role of activated charcoal in overdose management when appropriate?
- Adsorb drug in GI tract to reduce absorption. Binds toxins in the gastrointestinal lumen to limit systemic absorption and enhance fecal excretion.
- Which antidote reverses warfarin anticoagulation in major bleeding or urgent procedures?
- 4-factor PCC plus vitamin K. PCC rapidly replenishes clotting factors, while vitamin K sustains long-term reversal of warfarin.
- Which antidote is first-line for organophosphate or carbamate poisoning with cholinergic symptoms?
- Atropine. Blocks muscarinic receptors to counteract excessive cholinergic activity from cholinesterase inhibition.
- Which antidote is used for hypoglycemia caused by insulin or sulfonylurea exposure?
- Dextrose. Provides immediate glucose to correct severe hypoglycemia from excessive insulin or sulfonylurea action.
- What is a major risk of flumazenil in chronic benzodiazepine users or mixed overdoses?
- Seizures. Precipitates withdrawal in dependent users or unmasks convulsant effects in polydrug overdoses.
- Which antidote is used for calcium channel blocker overdose to improve hypotension?
- Calcium salts (calcium chloride or calcium gluconate). Overcomes channel blockade by increasing extracellular calcium to stabilize cardiac membranes.
- What is the key lab value used to assess acetaminophen overdose severity and guide NAC need?
- Serum acetaminophen concentration with time since ingestion. Plotted on the Rumack-Matthew nomogram to predict hepatotoxicity risk and determine treatment necessity.
- Which therapy is recommended for refractory beta-blocker or calcium channel blocker overdose?
- High-dose insulin euglycemia therapy (HIE). Enhances myocardial carbohydrate metabolism to provide inotropic support in refractory poisoning.
- What is the preferred initial decontamination method for corrosive (acid/alkali) ingestion?
- No GI decontamination; supportive care and urgent evaluation. Prevents further tissue injury by avoiding emesis or lavage that could exacerbate corrosive damage.
- Which antidote treats methemoglobinemia from oxidizing agents when symptomatic?
- Methylene blue. Accelerates methemoglobin reduction to hemoglobin via the NADPH-methemoglobin reductase pathway.
- Which antidote is used for heparin-induced bleeding or excessive anticoagulation?
- Protamine sulfate. Forms stable complexes with heparin to neutralize its anticoagulant effects and stop bleeding.
- What adjunct antidote reactivates acetylcholinesterase in organophosphate poisoning?
- Pralidoxime (2-PAM). Regenerates inhibited acetylcholinesterase by cleaving the organophosphate-enzyme bond.
- Which antidote is used for life-threatening bleeding from apixaban or rivaroxaban?
- Andexanet alfa. Serves as a decoy target for factor Xa inhibitors to restore normal hemostasis.