Amphetamine & Cocaine Overdose

Essentials of Diagnosis

• Agitation, paranoia, psychosis

• Seizures, hyperthermia

• Hypertension, tachycardia

• Hyponatremia may occur with methylenedioxymethamphetamine (MDMA, "ecstasy")

General Considerations

• Amphetamines and cocaine are widely abused for their euphorigenic and stimulant properties

• Both drugs may be smoked, snorted, ingested, or injected

• The toxic dose of each drug is highly variable and depends on the route of administration and individual tolerance

• Amphetamine derivatives and related drugs include

  • Methamphetamine ("crystal meth," "crank")

  • MDMA

  • Ephedrine

  • Methcathinone ("cat" or "khat")

  • Methcathinone derivatives and related synthetic chemicals (eg, methylenedioxyprovalerone [MDPV] is often sold as purported "bath salts")

  • Amphetamine-like reactions have also been reported after use of synthetic cannabinoids (eg, "Spice" and "K2")

• Nonprescription medications and nutritional supplements may contain stimulant or sympathomimetic drugs, such as

  • Ephedrine

  • Yohimbine

  • Caffeine

Symptoms and Signs

• CNS stimulation and a generalized increase in central and peripheral sympathetic activity

• The onset of effects is most rapid after intravenous injection or smoking

• Anxiety

• Tremulousness

• Tachycardia

• Hypertension

• Diaphoresis

• Dilated pupils

• Agitation

• Muscular hyperactivity

• Psychosis

• In severe intoxication, seizures and hyperthermia may occur

• Prolonged use may cause cardiomyopathy

• Hyponatremia has been reported after MDMA use

Differential Diagnosis

• Pseudoephedrine, caffeine

• Anticholinergic poisoning

• Psychosis

• Heat stroke

• Alcohol or sedative-hypnotic withdrawal

• Serotonin syndrome

Laboratory Tests

• Urine screening usually tests for amphetamines, cocaine metabolite benzoylecgonine

• Blood screening is generally not sensitive enough to detect these drugs

Emergency and supportive measures

• Maintain patent airway and assist ventilation, if necessary

• Rapidly lower the body temperature (see Hyperthermia) in patients who are hyperthermic (39–40°C)

• Give intravenous fluids to prevent myoglobinuric kidney injury in patients who have rhabdomyolysis

Medications

• Treat agitation, psychosis, or seizures with a sedating benzodiazepine such as diazepam, 5–10 mg, or lorazepam, 2–3 mg intravenously

• Add phenobarbital (15 mg/kg intravenously) for persistent seizures

• Treat hypertension with a vasodilator drug, such as phentolamine (1–5 mg intravenously), or nitroprusside, or a combined alpha- and beta-adrenergic blocker (such as labetalol, 10–20 mg intravenously)

  • Do not administer a pure beta-blocker, such as propranolol alone, because this may result in paradoxic worsening of the hypertension as a result of unopposed alpha-adrenergic effects

• Treat tachycardia or tachyarrhythmias with a short-acting beta-blocker such as esmolol, 25–100 mcg/kg/min by intravenous infusion

• Treat hyponatremia (see Hyponatremia)

• Treat hyperthermia (see Hyperthermia)

Complications

• Sustained or severe hypertension may result in

  • Intracranial hemorrhage

  • Aortic dissection

  • Myocardial infarction

• Hyperthermia may cause

  • Multiorgan failure

  • Permanent brain damage

• Muscle hyperactivity may lead to metabolic acidosis and rhabdomyolysis

Prognosis

• Good prognosis if only a single brief seizure or if only mild-moderate agitation or if only cardiovascular effects

• Poor prognosis after severe hyperthermia (eg, temperature > 40°C) or intracranial hemorrhage

When to Admit

• Persistent hypertension, tachycardia

• Hyperthermia

• Hyponatremia

• Multiple or prolonged seizures