Mastering Medical
USMLE Step 1 · Psychiatry

Cocaine intoxication vs Amphetamine intoxication

How to tell Cocaine intoxication and Amphetamine intoxication apart when a board question makes them look alike.

Fastest separator

Both are sympathomimetic; cocaine is shorter with coronary vasospasm and sodium-channel effects, while amphetamines are longer with monoamine release and prolonged psychosis/insomnia.

Side by side

Cocaine intoxicationAmphetamine intoxication
Key clue

Cocaine intoxication is a short-acting sympathomimetic state with euphoria, agitation, mydriasis, diaphoresis, tachycardia, hypertension, chest pain, coronary vasospasm, stroke risk, and local anesthetic sodium-channel effects.

Amphetamine intoxication is longer-acting sympathomimetic toxicity with euphoria, alertness, agitation, mydriasis, bruxism, insomnia, anorexia, psychosis, and hyperthermia.

Mechanism

Cocaine blocks reuptake of dopamine, norepinephrine, and serotonin and also blocks sodium channels.

Amphetamines increase release of monoamines, especially dopamine and norepinephrine, producing prolonged stimulant effects.

Labs and tests

Chest pain, MI, arrhythmia, stroke, nasal septal perforation, crack lung, and urine benzoylecgonine support cocaine exposure.

Long duration, severe insomnia, formication, psychosis, dental bruxism, methamphetamine context, and urine amphetamine support amphetamine exposure.

The trap

Toxidrome overlap is large, so the exam often uses route, duration, chest pain/vasospasm, bruxism, or urine metabolite clues.

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The repair move

For stimulant intoxication, first name sympathomimetic toxicity, then use duration and exposure clues to separate cocaine from amphetamines.

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Core

A patient has euphoria, agitation, mydriasis, diaphoresis, hypertension, tachycardia, chest pain, and ST changes shortly after using a white powder intranasally. Which intoxication is most likely?

Show answer and explanation

Answer: A. Cocaine intoxication. Short-acting sympathomimetic toxicity with chest pain and coronary vasospasm after intranasal powder supports cocaine intoxication.

Why the other choices are tempting

  • B. Amphetamine intoxication is also sympathomimetic but often longer acting with prolonged insomnia/psychosis clues.
  • C. Opioid intoxication causes miosis and respiratory depression.
  • D. Benzodiazepine intoxication causes CNS depression with relatively preserved respirations in isolated overdose.
  • E. Alcohol withdrawal follows cessation and causes tremor/autonomic hyperactivity.

Flashcards

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What neurotransmitter action does cocaine block?

Cocaine blocks reuptake of dopamine, norepinephrine, and serotonin.

What cardiac clue strongly supports cocaine toxicity?

Chest pain or MI from coronary vasospasm strongly supports cocaine toxicity.

Quick answers

What is the fastest way to tell Cocaine intoxication from Amphetamine intoxication?

Both are sympathomimetic; cocaine is shorter with coronary vasospasm and sodium-channel effects, while amphetamines are longer with monoamine release and prolonged psychosis/insomnia.

What is the key clue for Cocaine intoxication?

Cocaine intoxication is a short-acting sympathomimetic state with euphoria, agitation, mydriasis, diaphoresis, tachycardia, hypertension, chest pain, coronary vasospasm, stroke risk, and local anesthetic sodium-channel effects.

What is the key clue for Amphetamine intoxication?

Amphetamine intoxication is longer-acting sympathomimetic toxicity with euphoria, alertness, agitation, mydriasis, bruxism, insomnia, anorexia, psychosis, and hyperthermia.

What is the common trap with Cocaine intoxication vs Amphetamine intoxication?

Toxidrome overlap is large, so the exam often uses route, duration, chest pain/vasospasm, bruxism, or urine metabolite clues.