What is the treatment for methamphetamine overdose?

Methamphetamine Overdose Treatment

Benzodiazepines are the first-line treatment for methamphetamine overdose, addressing agitation, hypertension, tachycardia, and psychosis, while beta-blockers must be strictly avoided as they worsen coronary vasospasm through unopposed alpha-adrenergic stimulation. 1

Initial Assessment and Stabilization

• Immediately assess airway, breathing, circulation, and neurological status upon presentation 1
• Obtain a 12-lead ECG to evaluate for cardiac ischemia, arrhythmias, ST elevation, or other cardiovascular complications 1
• Measure cardiac biomarkers (troponin) to assess for myocardial injury, as methamphetamine causes true acute coronary syndromes through coronary vasospasm, increased platelet aggregation, and can precipitate STEMI even in patients with normal coronary arteries 1
• Check creatinine phosphokinase levels to evaluate for rhabdomyolysis 2

Primary Pharmacological Management

Benzodiazepines as First-Line Therapy

• Administer benzodiazepines (lorazepam or diazepam) intravenously as the cornerstone of treatment for sympathomimetic toxidrome 1
• Benzodiazepines effectively manage agitation, hypertension, tachycardia, psychosis, and reduce metabolic heat production 1
• Lorazepam can be dosed intravenously with repeat dosing every 30 minutes if sedation remains inadequate 2
• Benzodiazepines can be combined with nitroglycerin for better control of hypertension and tachycardia 1

Alternative Sedation (When Benzodiazepines Insufficient)

• Droperidol produces more rapid and profound sedation than lorazepam for methamphetamine toxicity, with significantly improved sedation scores at 10,15,30, and 60 minutes, and requires fewer repeat doses 2
• However, current guidelines prioritize benzodiazepines as first-line, with antipsychotics reserved for refractory cases 1

Management of Cardiovascular Complications

Chest Pain and Suspected Coronary Vasospasm

• Administer sublingual nitroglycerin or intravenous calcium channel blockers (e.g., diltiazem 20 mg IV) as first-line therapy for chest pain with suspected coronary vasospasm 1
• Manage patients with chest pain and ECG changes as non-ST-elevation acute coronary syndrome (NSTE-ACS) but avoid beta-blockers 1
• If ST elevation persists despite nitroglycerin and calcium channel blockers, or if cardiac biomarkers are positive, proceed to immediate coronary angiography 1

Critical Medication Contraindications

• Strictly avoid pure beta-blockers in acute methamphetamine intoxication, as they worsen coronary vasospasm by allowing unopposed alpha-adrenergic stimulation 1
• Combined alpha-beta blockers should also be avoided or used with extreme caution for the same reason 1
• This contraindication applies only to patients with signs of acute intoxication (euphoria, tachycardia, hypertension); patients with remote methamphetamine use history but no acute intoxication can receive standard therapies including beta-blockers 1

Management of Life-Threatening Hyperthermia

Indications for Intubation

• Immediately intubate patients with severe hyperthermia (temperature >40°C or 104°F) who remain agitated despite maximal benzodiazepine sedation 1
• Continued agitation indicates inability to control metabolic heat production and prevents effective cooling measures 1
• Rhabdomyolysis risk is imminent at high temperatures with ongoing muscle activity, leading to renal failure and death 1

Post-Intubation Management

• Paralyze and sedate with continuous benzodiazepine infusion to eliminate muscle heat production 1
• Implement aggressive cooling measures simultaneously: chilled saline bolus and external cooling 1
• Treat hyperkalaemia with dextrose and insulin, and calcium chloride 1
• Maintain urine output to prevent myoglobin-induced renal failure with furosemide and mannitol 1

Critical Pitfall

• Do not delay intubation waiting for additional benzodiazepines to work—every minute at high temperatures causes irreversible organ damage 1
• Mortality approaches 11% in severe sympathomimetic toxicity with hyperthermia, with significant morbidity from rhabdomyolysis, renal failure, seizures, and disseminated intravascular coagulation 1

Monitoring and Observation

• Patients with ECG changes and normal initial cardiac biomarkers require monitored observation for 24 hours, as most methamphetamine-related cardiac complications occur within this timeframe 1
• A shorter observation period of 9-12 hours with serial troponin measurements at 3,6, and 9 hours may be appropriate in select cases with normal ECG and negative initial biomarkers 1
• Monitor vital signs continuously: both benzodiazepines and droperidol produce significant reductions in pulse, systolic blood pressure, respiratory rate, and temperature over 60 minutes 2

Special Considerations

• Methamphetamine-related cardiac complications can occur even with normal coronary arteries due to vasospasm 1
• Up to 30% of STEMI patients present with atypical symptoms, and methamphetamine users frequently have atypical presentations that can mask true cardiac events 1
• ST elevation meeting STEMI criteria (≥0.1 mV in at least 2 contiguous limb leads or ≥0.2 mV in 2 contiguous precordial leads) demands urgent assessment even if attributed to methamphetamine use 1
• Patients rarely seek medical attention for methamphetamine-related undesirable effects, which they term "overamping," and have few harm reduction strategies at their disposal 3