What is the treatment for methamphetamine (meth) intoxication in the Emergency Department (ED)?

Treatment of Methamphetamine Intoxication in the Emergency Department

The treatment of methamphetamine intoxication in the emergency department should focus on benzodiazepines as first-line agents for agitation and autonomic hyperactivity, with additional supportive care based on specific clinical manifestations. 1

Initial Assessment and Management

Clinical Presentation

• Acute behavioral disturbance: Present in approximately 78% of methamphetamine intoxication cases 2
• Vital sign abnormalities:
  • Tachycardia (56% of presentations)
  • Hypertension (42% of presentations)
  • Hyperthermia (5% of presentations) 2
• Potential complications:
  • Rhabdomyolysis (30% of cases)
  • Acute kidney injury (13% of cases)
  • Less common: seizures, intracranial hemorrhage, myocardial infarction 2

Management Algorithm

1. Control agitation and autonomic hyperactivity:

   • First-line: Benzodiazepines (e.g., lorazepam 1-4mg IV/IM every 4-8 hours or diazepam 5-10mg IV/IM every 6-8 hours) 3, 1
   • Benzodiazepines help manage agitation, reduce sympathetic overstimulation, and prevent complications like seizures

2. For severe agitation unresponsive to benzodiazepines:

   • Consider droperidol as an alternative, which has been shown to produce more rapid and profound sedation than lorazepam for methamphetamine toxicity 4
   • Caution: Beta-blockers are relatively contraindicated as they do not effectively reduce coronary vasoconstriction and may worsen hypertension by leaving alpha effects unopposed 1

3. For cardiovascular manifestations:

   • Hypertension/tachycardia: Calcium channel blockers (e.g., diltiazem 20mg IV) or nitrates are preferred 1
   • Chest pain with ECG changes: Treat with nitrates and calcium channel blockers 1
   • For coronary vasospasm: Nitrates and calcium channel blockers are recommended 1

4. For hyperthermia:

   • Active cooling measures for temperature >39°C 2
   • Ensure adequate hydration

5. Supportive care:

   • IV fluids for dehydration and to prevent rhabdomyolysis
   • Monitor for and treat electrolyte abnormalities
   • Monitor cardiac status with continuous ECG
   • Consider checking creatine kinase levels to assess for rhabdomyolysis 2

Special Considerations

Cardiac Complications

• If chest pain with ST-segment elevation is present:
  • Administer sublingual nitroglycerin or calcium channel blockers 1
  • Consider coronary angiography for persistent symptoms 1
  • Avoid beta-blockers (including labetalol) as they may worsen coronary vasoconstriction 1

Psychiatric Manifestations

• Methamphetamine-induced psychosis may require longer observation periods 5
• For persistent psychosis after acute intoxication resolves, psychiatric consultation is recommended
• Approximately 11% of methamphetamine intoxication cases require mental health admission 2

Disposition

• Most patients (84%) can be managed solely within the ED 2
• Median length of stay is approximately 14 hours 2
• Discharge criteria:
  • Resolution of agitation and psychosis
  • Stable vital signs
  • No evidence of end-organ damage requiring admission

Pitfalls and Caveats

1. Avoid beta-blockers: They may worsen coronary vasoconstriction in methamphetamine toxicity 1

2. Monitor for delayed complications: Rhabdomyolysis and acute kidney injury can develop hours after presentation 2

3. Consider co-ingestions: Methamphetamine is often used with other substances that may require additional management approaches 2

4. Recognize methamphetamine-associated psychosis: May persist beyond the acute intoxication phase and require specialized psychiatric care 5

5. Chemical restraint considerations: Methamphetamine users have 3.2 times higher odds of requiring chemical restraint compared to non-drug users 6, so be prepared to escalate sedation if needed

The majority of patients with methamphetamine intoxication can be successfully managed in the ED with appropriate sedation and supportive care, with most being discharged after resolution of symptoms 2.