11. Stimulant (Cocaine, Amphetamine) Overdose and Intoxication

Mechanism and Pharmacokinetics

  • Amphetamines: CNS stimulation and sympathetic stimulation via inhibition of catecholamine reuptake and stimulation of monoamine release. Lasts up to several hours.
  • Cocaine: similar to amphetamines; in addition, it is a local anesthetic with sodium-channel blocking effects similar to TCAs. Lasts 30 minutes to several hours.

Signs, Symptoms, and Complications

  • Neuropsychiatric: severe agitated delirium, mydriasis, agitation, delirium, psychosis, rigidity, brief seizures, intracranial hemorrhage/CVA.
  • Cardiac: hypertension, tachycardia, arrhythmias, coronary vasospasm/thrombosis, MI (even without underlying coronary artery disease), aortic dissection. See also Cardiology: Cocaine-induced chest pain. Cocaine also causes cardiac conduction defect (wide QRS interval) similar to TCAs.
  • Pulmonary: hemorrhagic alveolitis, barotrauma (pneumothorax or pneumomediastinum) from deep inhalation.
  • Renal: renal failure secondary to renovascular spasm/shock/rhabdomyolysis with myoglobinuria.
  • Systemic: hyperthermia is common and can be life threatening, rhabdomyolysis.
  • Differential diagnosis: other adrenergic toxidromes, neuroleptic malignant syndrome, serotonin syndrome, thyroid storm, intracranial hemorrhage.

Evaluation

  • BMP, CK, lactate, LFTs, coagulation studies, and urinalysis (look for myoglobin). If diagnosis unclear, consider TFTs and obtain detailed medication history.
  • Urine toxicology is generally reliable for cocaine; less useful for amphetamines because many false positives and false negatives (amphetamine derivatives and analogs).
  • Depending on presentation, troponin, ECG, CXR, and non-contrast head CT (if suspected cerebral hemorrhage).

Management

In general, many effects, including agitation, tachycardia and hypertension, are mediated by CNS stimulatory effects and will respond to sedatives. Start with benzodiazepines IV PRN; can escalate to antipsychotics as needed when benzodiazepines do not control agitation.

  • ABCs, vital signs (including rectal temperature) and telemetry.
    • Succinylcholine is a relative contraindication as it can worsen rhabdomyolysis-mediated hyperkalemia. Non-depolarizing agents (rocuronium, vecuronium) are preferred.
  • Cocaine-induced QRS prolongation: rare, due Na+ channel blockade. Treat with sodium bicarbonate boluses.
  • Supraventricular tachycardia: treat as you would in other etiologies (see cardiology SVT section). Avoid beta-blockers. Calcium channel blockers are safe to use (e.g., diltiazem).
  • Ventricular tachycardia: follow ACLS; additionally, bolus bicarbonate to counteract direct action of cocaine on Na+ channels.
  • Hypertension: try benzodiazepines for sedative effects. If refractory, treat as any other malignant hypertension. Avoid sole use of beta-blockers because of the concern for unopposed alpha-stimulation (controversial).
  • Agitation and psychosis: benzodiazepines PRN; may require high doses. Consider antipsychotic drugs such as haloperidol or olanzapine, though caution in patients with hyperthermia and QTc prolongation.
  • Seizures: benzodiazepines IV/IM. If status epilepticus, consider other causes, including absorption from broken bag or packet of drug in GI tract.
  • Hyperthermia: manage aggressively (See Drug-Induced Hyperthermia section); can lead to death. Severe cases will require paralysis and mechanical ventilation.
    • Neuroleptics can interfere with heat dissipation; caution using these medications.
    • Antipyretics have no role, as increased body temperature in stimulant intoxication is from muscle activity rather than alteration in hypothalamic set point.
  • Drug packet ingestion (“body packing” or “body stuffing”): decontamination via whole bowel irrigation may be indicated (consult Poison Control, gastroenterology). Severe abdominal pain may necessitate immediate laparotomy to prevent bowel ischemia from local vasoconstriction.
    • Gastric lavage likely has NO benefit.
  • Levamisole: antihelminthic drug mostly used in veterinary medicine. Increasingly used as a cocaine adulterant. Can cause life-threatening agranulocytosis and leukoencephalopathy. Retiform purpura and leukocytoclastic vasculitis with cutaneous necrosis are also linked to levamisole.

Withdrawal

In patients who use stimulants, abrupt discontinuation or decreased use can cause withdrawal syndrome, usually within hours.

  • Symptoms: dysphoria, anhedonia, fatigue, vivid dreams, insomnia, hypersomnia, agitation, anxiety, cravings, appetite changes.
  • Withdrawal will peak within 1-2 days, and resolve within 1-3 weeks.
  • No evidence-based treatment for withdrawal though bupropion has limited data in stimulant-withdrawal dysphoria. Supportive care and symptom-based management are recommended.

 

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