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

Treatment of Methamphetamine Intoxication in Emergency Department

The management of methamphetamine intoxication in the ED should focus on symptomatic treatment with benzodiazepines for agitation, nitrates and calcium channel blockers for cardiovascular symptoms, and supportive care for complications. 1

Initial Assessment and Stabilization

• Vital Signs Monitoring: Continuous monitoring of heart rate, blood pressure, temperature, and oxygen saturation
• Laboratory Tests:
  • Urine toxicology screen (positive for methamphetamine within 1-4 hours of use, remains positive for 2-4 days) 1
  • Cardiac markers (troponin preferred over CK/CK-MB due to higher specificity) 1
  • Basic metabolic panel to assess renal function
  • Creatine kinase to evaluate for rhabdomyolysis

Management Algorithm

1. Agitation and Behavioral Disturbance (Most Common Presentation)

• First-line: Oral benzodiazepines for mild-moderate agitation 2
• Second-line: Parenteral benzodiazepines for severe agitation or if oral administration not feasible
• Avoid: Beta-blockers alone (may worsen coronary vasoconstriction) 1

2. Cardiovascular Symptoms

• Chest Pain/Ischemia:

  • Sublingual nitroglycerin or IV calcium channel blockers (e.g., diltiazem 20 mg IV) 1
  • ECG monitoring for ST-segment changes
  • If ST-elevation persists despite nitrates/calcium channel blockers, consider coronary angiography 1

• Hypertension:

  • Nitrates and calcium channel blockers are preferred 1
  • Consider labetalol (combined alpha/beta blocker) if severe hypertension persists 1

• Tachycardia:

  • Calcium channel blockers (verapamil has been shown to reverse methamphetamine-induced tachycardia) 1

3. Hyperthermia Management

• Active cooling for temperatures >39°C 2, 3
• IV fluids to maintain hydration

4. Management of Complications

• Rhabdomyolysis:

  • IV fluid hydration
  • Monitor creatine kinase, renal function
  • Consider alkalinization of urine if severe

• Seizures:

  • IV benzodiazepines (lorazepam or diazepam)
  • If refractory, consider loading with levetiracetam or phenytoin

• Acute Kidney Injury:

  • IV fluid resuscitation
  • Monitor urine output
  • Consider nephrology consultation for severe cases 3

Disposition

• Most patients (approximately 84%) can be managed solely within the ED 2
• Median observation time: 9-14 hours 1, 2
• Indications for admission:
  • Persistent vital sign abnormalities
  • Significant end-organ damage (renal failure, cardiac injury)
  • Severe psychiatric symptoms requiring inpatient management
  • Recurrent seizures

Special Considerations and Pitfalls

• Avoid beta-blockers alone: May worsen coronary vasoconstriction in methamphetamine toxicity 1
• Recognize mimics: Methamphetamine can cause CK and CK-MB elevation due to increased motor activity and skeletal muscle injury, which may mimic MI; troponin is more specific 1
• Watch for delayed complications: Monitor for at least 6-9 hours with serial cardiac markers 1
• Consider co-ingestions: Methamphetamine is often used with other substances that may complicate management 4
• Poor prognostic signs: Coma, shock, convulsions, oliguria, high body temperature (>41°C), acidosis, and acute renal failure 3

Discharge Considerations

• Ensure resolution of acute symptoms and normalization of vital signs
• Consider referral to addiction treatment services
• Patient education on risks of continued use
• Non-judgmental approach to improve future healthcare engagement 5

The treatment approach for methamphetamine intoxication is similar to that for cocaine intoxication due to similarities in their pathophysiology 1. This approach prioritizes managing the sympathomimetic effects while avoiding medications that could worsen coronary vasoconstriction.