5-Minute Emergency Consult

Amphetamine Poisoning

Description

  • Increased release of norepinephrine, dopamine and serotonin
  • Decreased catecholamine reuptake
  • Direct effect on α- and β-adrenergic receptors

Etiology

  • Prescription drugs:
    • Amphetamine (Benzedrine)
    • Dextroamphetamine (Dexedrine)
    • Diethylpropion (Tenuate)
    • Fenfluramine (Pondimin)
    • Methamphetamine
    • Methylphenidate (Ritalin)
    • Phenmetrazine (Preludin)
    • Phentermine
  • “Designer drugs”:
    • Variants of illegal parent drugs
    • Often synthesized in underground laboratories
    • “Crystal,” “Ice”:
      • Crystalline methamphetamine hydrochloride
      • Smoked, insufflated, or injected
      • Rapid onset; duration several hours
    • “Crank”
    • “Ecstasy” (3,4,- methylenedioxymetham-phetamine, MDMA, XTC, E):
      • Often used at dances and “rave” parties
      • Dehydration can lead to hyperthermia, hyponatremia, fatality.
    • MDA (3,4,-methylenedioxyamphetamine)
    • Methcathinone (“cat,” “Jeff,” “mulka”):
      • Derivative of cathinone, found in the evergreen tree Catha edulis
      • Frequently synthesized in home laboratories
      • Does not show up on urine toxicology screens

Signs and Symptoms

  • CNS:
    • Agitation
    • Delirium
    • Hyperactivity
    • Tremors
    • Dizziness
    • Mydriasis
    • Headache
    • Choreoathetoid movements
    • Hyperreflexia
    • Cerebrovascular accident
    • Seizures and status epilepticus
    • Coma
  • Psychiatric:
    • Euphoria
    • Increased aggressiveness
    • Anxiety
    • Hallucinations (visual, tactile)
    • Compulsive repetitive actions
  • Cardiovascular:
    • Palpitations
    • Hypertensive crisis
    • Tachycardia or (reflex) bradycardia
    • Dysrhythmias (usually tachydysrhythmias)
    • Cardiovascular collapse
  • Other:
    • Rhabdomyolysis
    • Myoglobinuria
    • Acute renal failure
    • Anorexia
    • Diaphoresis
    • Disseminated intravascular coagulation (DIC)

History
  • Determine the type, amount, timing, and route of amphetamine exposure
  • Assess for possible coingestions
  • Evaluate for symptoms of end organ injury:
    • Chest pain
    • Shortness of breath
    • Headache, confusion and vomiting

Physical Exam
  • Common findings include:
    • Agitation
    • Tachycardia
    • Diaphoresis
    • Mydriasis
  • Severe intoxication characterized by:
    • Tachycardia
    • HTN
    • Hyperthermia
    • Agitated delirium
    • Seizures
    • Diaphoresis
  • Hypotension and respiratory distress may precede cardiovascular collapse.
  • Evaluate for associated conditions;
    • Cellulitis and soft tissue infections
    • Diastolic cardiac murmurs or unequal pulses
    • Examine carefully for trauma
    • Pneumothorax from inhalation injury
    • Focal neurological deficits

Essential Workup

  • Vital signs:
    • Temperature >40°C:
      • Core temperature recording essential
      • Peripheral temperature may be cool.
      • Indication for urgent cooling
      • Ominous prognostic sign
    • BP:
      • Severe hypertension can lead to cardiac and neurologic abnormalities.
      • Late in course, hypotension may supervene.
  • ECG:
    • Signs of cardiac ischemia
    • Ventricular tachydysrhythmias
    • Reflex bradycardia

Diagnostic Tests and Interpretation

Lab

  • Urinalysis:
    • Blood
    • Myoglobin
  • Electrolytes, BUN/creatinine, glucose:
    • Hypoglycemia may contribute to altered mental status.
    • Acidosis may accompany severe toxicity.
    • Rhabdomyolysis may cause renal failure.
    • Hyperkalemia—life-threatening consequence of acute renal failure
  • Coagulation profile to monitor for potential DIC:
    • INR, PT, PTT, platelets
  • Creatine phosphokinase (CPK):
    • Markedly elevated in rhabdomyolysis
  • Urine toxicology screen:
    • For other toxins with similar effects (eg, cocaine)
    • Some amphetaminelike substances (eg, methcathinone) may not be detected.
  • Aspirin and acetaminophen levels if suicide attempt a possibility
  • Arterial blood gas (ABG)

Imaging
  • Chest radiograph:
    • Adult respiratory distress syndrome
    • Noncardiogenic pulmonary edema
  • Head CT for:
    • Significant headache
    • Altered mental status
    • Focal neurologic signs
    • For subarachnoid hemorrhage, intracerebral bleed

Diagnostic Procedures/Other
Lumbar puncture for:
  • Suspected meningitis (headache, altered mental status, hyperpyrexia)
  • Suspected subarachnoid hemorrhage and CT normal

Differential Diagnosis

  • Sepsis
  • Thyroid storm
  • Serotonin syndrome
  • Neuroleptic malignant syndrome
  • Pheochromocytoma
  • Subarachnoid hemorrhage
  • Drugs that cause delirium:
    • Anticholinergics:
      • Belladonna alkaloids
      • Antihistamines
    • Tricyclic antidepressants
    • Cocaine
    • Ethanol withdrawal
    • Sedative/hypnotic withdrawal
    • Hallucinogens
    • Phencyclidine
  • Drugs that cause HTN and tachycardia:
    • Sympathomimetics
    • Anticholinergics
    • Ethanol withdrawal
    • Phencyclidine
    • Caffeine
    • Phenylpropanolamine
    • Ephedrine
    • Monoamine oxidase inhibitors
    • Theophylline
    • Nicotine
  • Drugs that cause seizures:
    • Carbon monoxide
    • Carbamazepine
    • Cyanide
    • Cocaine
    • Cholinergics (organophosphate insecticides)
    • Camphor
    • Chlorinated hydrocarbons
    • Ethanol withdrawal
    • Sedative/hypnotic withdrawal
    • Isoniazid
    • Theophylline
    • Hypoglycemics
    • Lead
    • Lithium
    • Local anesthetics
    • Anticholinergics
    • Phencyclidine
    • Phenothiazines
    • Phenytoin
    • Propoxyphene
    • Salicylates
    • Strychnine

Pre Hospital

  • Patient may be uncooperative or violent.
  • Secure IV access.
  • Protect from self-induced trauma.

Initial Stabilization/Therapy

  • ABCs
  • Establish IV 0.9% NS access.
  • Cardiac monitor
  • Naloxone, dextrose (or Accu-Chek), and thiamine if altered mental status

Ed Treatment/Procedures

  • Decontamination:
    • Gastric lavage:
      • Consider if recent (within 1 hr) or life-threatening ingestion.
      • Instill activated charcoal through large-bore orogastric tube both before and after lavage.
    • Administer activated charcoal with sorbitol:
      • Consider if recent ingestion
    • Whole-bowel irrigation with polyethylene glycol solution for body packers
  • Hypertensive crisis:
    • Initially administer benzodiazepines if agitated.
    • Alpha-blocker (phentolamine) as second-line agent
    • Nitroprusside for severe, unresponsive hypertension
    • Avoid β-blockers, which may exacerbate hypertension.
  • Agitation, acute psychosis:
    • Administer benzodiazepines.
  • Hyperthermia:
    • Benzodiazepines if agitated
    • Active cooling if temperature >40°C:
      • Tepid water mist
      • Evaporate with fan.
    • Paralysis:
      • Indicated if muscle rigidity and hyperactivity contributing to persistent hyperthermia
      • Nondepolarizing agent (eg, vecuronium)
      • Avoid succinylcholine.
      • Intubation; mechanical ventilation
    • Apply cooling blankets.
  • Rhabdomyolysis:
    • Administer benzodiazepines.
    • Hydrate with 0.9% NS.
    • Maintain urine output at 1–2 mL/min.
    • Hemodialysis (if acute renal failure and hyperkalemia occur)
  • Seizures:
    • Maintain airway.
    • Administer benzodiazepines.
    • Phenobarbital if unresponsive to benzodiazepines
    • Phenytoin contraindicated

Medication

  • Activated charcoal: 1–2 g/kg up to 100 g PO
  • Dextrose: D50W 1 amp: 50 mL or 25 g (peds: D25W 2–4 mL/kg) IV
  • Diazepam (benzodiazepine): 5–10 mg (peds: 0.2–0.5 mg/kg) IV
  • Lorazepam (benzodiazepine): 2–6 mg (peds: 0.03–0.05 mg/kg) IV
  • Nitroprusside: 1–8 μg/kg/min IV (titrated to BP)
  • Phenobarbital: 15–20 mg/kg at 25–50 mg/min until cessation of seizure activity
  • Phentolamine: 1–5 mg IV over 5 min (titrated to BP)
  • Sorbitol: 1–2 g/kg to a max. of 100 g PO mixed in the activated charcoal slurry (peds: >1 yr old: 1–1.5 g/kg as a 35% solution to a max. of 50 g); avoid repeat doses of sorbitol.
  • Vecuronium: 0.1 mg/kg IVP

Disposition

Admission Criteria

  • Hyperthermia
  • Persistent altered mental status
  • Hypertensive crisis
  • Seizures
  • Rhabdomyolysis
  • Persistent tachycardia

Discharge Criteria
  • Asymptomatic after 6 hr observation
  • Absence of above admission criteria

Follow-Up Recommendations

Patients may need referral for chemical dependency rehab and detoxification.

Pearls and Pitfalls

  • Admit patients with severe or persistent symptoms.
  • Monitor core temperature:
    • Hyperthermia >40°C may be life threatening.
    • Treat with aggressive sedation and active cooling.
    • Recognize rhabdomyolysis and hyperkalemia.
    • Avoid physical restraints in agitated patients if possible.
  • Consider associated emergency conditions:
    • Patients with chest pain should be evaluated for acute coronary syndromes and treated accordingly.
    • Consider infection in altered patients with fevers and history of IV drug use.
    • Methamphetamine abuse frequently associated with traumatic injury
  • Benzodiazepines are 1st-line therapy in symptomatic methamphetamine intoxication.

[GENERAL]

  • Callaway CW, Clark RF. Hyperthermia in psychostimulant overdose. Ann Emerg Med. 1994;24:68–75.
  • Chan P, Chen JH, Lee MH, et al. Fatal and nonfatal methamphetamine intoxication in the intensive care unit. Clin Toxicol. 1994;32:147–155.
  • Christophersen AS. Amphetamine designer drugs—An overview and epidemiology. Toxicol Lett. 2000;112–113:127.
  • Doyon S. The many faces of ecstasy. Curr Opinion Pediatr. 2001;13:170–176.
  • Gray SD, Fatovich DM, McCoubrie DL, et al. Amphetamine-related presentations to and inner-city tertiary emergency department: A prospective evaluation. Med J Aust. 2007;186:336.
  • Turnipseed SD, Richards JR, Kirk JD, et al. Frequency of acute coronary syndrome in patients presenting to the emergency department with chest pain after methamphetamine use. J Emerg Med. 2003;24(4):369–373.

See Also

ICD-9

969.72 Poisoning by amphetamines

SNOMED

45775001 poisoning by amphetamine (disorder)

Authors

Seth M. Oskie
James W. Rhee


© Wolters Kluwer Health Lippincott Williams & Wilkins

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