What is the management of a methamphetamine overdose?

Management of Methamphetamine Overdose

Immediate Stabilization and Assessment

Administer benzodiazepines as first-line therapy for all patients presenting with methamphetamine overdose to manage agitation, hypertension, tachycardia, and psychosis. 1

Initial Actions

• Assess airway, breathing, circulation, and neurological status immediately upon patient arrival 1
• Obtain a 12-lead ECG immediately to evaluate for cardiac ischemia, arrhythmias, ST elevation, or other cardiovascular complications 1
• Check 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
• Obtain urine toxicology to confirm amphetamine presence (remains positive for 2-4 days) 2

Primary Pharmacological Management

Benzodiazepines (First-Line)

• Benzodiazepines alone or combined with nitroglycerin are the first-line treatment for sympathomimetic toxidrome 1
• Oral sedation successfully manages acute behavioral disturbance in 61% of patients, with parenteral sedation reserved for those not responding to oral therapy 3
• Benzodiazepines can be combined with nitroglycerin for better control of hypertension and tachycardia 1

Management of 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
• If ST elevation persists despite nitroglycerin and calcium channel blockers, or if cardiac biomarkers are positive, proceed to immediate coronary angiography 1
• Manage patients with chest pain and ECG changes as non-ST-elevation acute coronary syndrome (NSTE-ACS) but strictly avoid beta-blockers 1

Critical Medication to AVOID

• Strictly avoid pure beta-blockers in acute methamphetamine intoxication, as they worsen coronary vasospasm by allowing unopposed alpha-adrenergic stimulation 1
• If combined alpha-beta blockers are needed for severe hypertension, use with extreme caution 1
• Patients with a history of methamphetamine use but without signs of acute intoxication can receive standard therapies including beta-blockers if indicated 1

Management of Life-Threatening Hyperthermia

Indications for Immediate Intubation

• Intubate immediately if continued agitation persists despite maximal sedation with severe hyperthermia, as this 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
• Seizures are likely with extreme hyperthermia and sympathomimetic toxicity, requiring airway protection 1

Post-Intubation Protocol

• 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, insulin, and calcium chloride 1
• Maintain urine output to prevent myoglobin-induced renal failure with furosemide and mannitol 1
• Do not delay intubation waiting for additional benzodiazepines to work, as every minute at high temperatures causes irreversible organ damage 1

Monitoring and Observation

Patients with ECG Changes

• Observe patients with ECG changes and normal cardiac biomarkers in a monitored setting for 24 hours, as most 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 1

Common Complications to Monitor

• Rhabdomyolysis occurs in 30% of presentations 3
• Acute kidney injury occurs in 13% of presentations 3
• Tachycardia occurs in 56% of presentations 3
• Hypertension occurs in 42% of presentations 3
• Hyperthermia occurs in 5% of presentations 3
• Rare but serious complications include seizures, intracranial hemorrhage, myocardial infarction, and subarachnoid hemorrhage 3

Special Considerations

Gastrointestinal Complications

• Maintain high clinical suspicion for gastrointestinal ischemia in any methamphetamine user presenting with acute abdominal symptoms, as methamphetamine causes gastrointestinal bleeding through ischemic injury by producing profound vasoconstriction and compromising mesenteric and gastric blood flow 2
• Gastrointestinal symptoms typically present within 1-4 hours of methamphetamine consumption 2

Disposition

• The majority (84%) of patients are managed solely within the ED with a median length of stay of 14 hours 3
• Mental health admission is required in 11% of presentations 3
• Mortality approaches 11% in severe sympathomimetic toxicity with hyperthermia 1

Critical Pitfalls to Avoid

• Never use beta-blockers in acute methamphetamine intoxication - they precipitate worse outcomes by allowing unopposed alpha-adrenergic vasoconstriction 1
• Do not dismiss ST elevation as "just methamphetamine use" - methamphetamine causes true myocardial infarction and demands urgent assessment, as up to 30% of STEMI patients present with atypical symptoms 1
• Do not delay intubation in severe hyperthermia - immediate action is required to prevent irreversible organ damage 1
• Do not use anti-hypertensives routinely - hypertension typically responds to benzodiazepines alone 3