Toxicology 1 นาทีในการอ่าน

Drug Overdose Management

Effective drug overdose management follows a systematic approach: stabilize, decontaminate, administer specific antidotes, and provide supportive care.

## Overview

Drug overdose is a leading cause of injury-related death globally. In the United States, over 100,000 drug overdose deaths occur annually. Successful management requires rapid assessment, stabilization, and targeted interventions.

## Initial Assessment and Stabilization

The ABCs (Airway, Breathing, Circulation) take priority. Endotracheal intubation may be needed for patients with depressed consciousness. IV access, continuous cardiac monitoring, and pulse oximetry are established immediately.

**Empiric interventions** include: naloxone (0.4-2 mg IV) if opioid overdose is suspected, dextrose (25-50 g IV) for altered mental status with possible hypoglycemia, and thiamine (100 mg IV) before glucose in suspected chronic alcohol use.

## Toxidrome Recognition

Identifying the clinical syndrome guides management:

- **Opioid**: Miosis, respiratory depression, decreased consciousness
- **Anticholinergic**: Mydriasis, tachycardia, dry skin, urinary retention, delirium
- **Sympathomimetic**: Mydriasis, tachycardia, hypertension, diaphoresis, agitation
- **Cholinergic**: SLUDGE (Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis)
- **Sedative-hypnotic**: CNS depression, respiratory depression, normal pupils

## Decontamination

**Activated charcoal** (1 g/kg, max 50 g) is most effective within 1-2 hours of ingestion. It adsorbs most drugs but is ineffective against metals, alcohols, and hydrocarbons. **Whole bowel irrigation** with polyethylene glycol is used for sustained-release formulations, iron, and body-packet ingestion. Gastric lavage and ipecac-induced emesis are rarely recommended in modern practice.

## Specific Antidotes

| Toxin | Antidote | Mechanism |
|---|---|---|
| Acetaminophen | N-acetylcysteine | Glutathione replenishment |
| Opioids | Naloxone | Mu-receptor antagonist |
| Benzodiazepines | Flumazenil | GABA-A antagonist (caution: seizures) |
| Organophosphates | Atropine + pralidoxime | Muscarinic blockade + AChE reactivation |
| Digoxin | Digoxin-specific antibodies | Fab fragment binding |
| Beta-blockers | Glucagon, high-dose insulin | Bypass beta-receptor blockade |
| Warfarin | Vitamin K, 4-factor PCC | Restore coagulation factors |

## Enhanced Elimination

**Urinary alkalinization** with sodium bicarbonate enhances salicylate and methotrexate excretion. **Hemodialysis** is effective for methanol, ethylene glycol, lithium, salicylates, and theophylline. **Multi-dose activated charcoal** interrupts enterohepatic recirculation of carbamazepine, dapsone, and theophylline.

## Key Takeaways

- Stabilize ABCs before any specific intervention
- Toxidrome recognition narrows the differential rapidly
- Activated charcoal is most effective within 1-2 hours of ingestion
- Naloxone, N-acetylcysteine, and atropine are among the most critical antidotes
- Hemodialysis removes small, water-soluble, low-protein-bound toxins

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