You’re cruising through your psych Q-bank when a patient rolls in sweaty, paranoid, and tachycardic—and suddenly every answer choice looks kind of right. Stimulant intoxication questions (cocaine, amphetamines) are classic USMLE territory because they test more than recognition: they test whether you can separate intoxication from withdrawal, know first-line acute management, and spot lethal mimics (thyroid storm, serotonin syndrome, anticholinergic toxicity, etc.). Let’s break it down the way the test actually works: one best answer, and a bunch of tempting distractors designed to punish fuzzy thinking.
Clinical Vignette (Q-Bank Style)
A 24-year-old man is brought to the ED by police for “bizarre behavior.” He is extremely agitated and pacing, shouting that people are “coming to get him.” Vitals: T 38.7°C (101.7°F), BP 178/104 mmHg, HR 132/min, RR 24/min, SpO₂ 98% RA. He is diaphoretic, has mydriasis, and is tremulous. Exam is notable for hyperreflexia. No rigidity is noted. He keeps trying to get off the stretcher. ECG shows sinus tachycardia.
Which is the most appropriate next step in management?
A. Administer IV lorazepam
B. Administer flumazenil
C. Administer haloperidol as monotherapy
D. Administer propranolol
E. Administer naloxone
The Correct Answer: A. Administer IV lorazepam
Why this is right
This is a prototypical stimulant intoxication presentation (cocaine or amphetamines):
- Sympathomimetic toxidrome: agitation, tachycardia, hypertension, hyperthermia, diaphoresis, mydriasis
- Psychiatric features: paranoia, psychosis
- Neuro findings: tremor, hyperreflexia (can be seen in stimulant toxicity; clonus points more to serotonin syndrome)
First-line acute treatment is benzodiazepines (e.g., lorazepam, diazepam) because they:
- Reduce CNS sympathetic outflow → lower HR/BP, calm agitation
- Treat and prevent seizures
- Help mitigate hyperthermia by stopping muscle overactivity and agitation
- Are rapid and broadly effective while you stabilize and evaluate
What else should you do (high-yield ED bundle)
Along with benzos, think:
- Active cooling for hyperthermia (external cooling, cold IV fluids as appropriate)
- IV fluids (rhabdo risk)
- Check glucose, BMP, CK, troponin (if chest pain), ECG
- Avoid restraints alone (worsens hyperthermia/rhabdo); if needed, pair with sedation
- If severe hypertension persists despite benzos: consider vasodilators (e.g., nitroprusside; nitroglycerin especially if cocaine chest pain)
High-Yield Pathophysiology (How USMLE Frames It)
Cocaine
- Mechanism: blocks reuptake of NE, DA, 5-HT; also Na⁺ channel blockade (local anesthetic)
- Key complications:
- Coronary vasospasm → MI (even in young patients)
- Arrhythmias (Na⁺ blockade)
- Aortic dissection, stroke
- Hyperthermia, seizures
Amphetamines (including meth, MDMA)
- Mechanism: ↑ release of DA and NE (and 5-HT with MDMA) and blocks reuptake
- Key complications:
- Severe agitation/psychosis
- Hyperthermia, rhabdomyolysis
- Hypertension, intracranial hemorrhage
Sympathomimetic toxidrome quick pattern
- “Hot, sweaty, fast, wide”: hyperthermia + diaphoresis + tachycardia + mydriasis
- Distinguish from anticholinergic: anticholinergic is dry (anhidrosis) and often has urinary retention.
Why Every Distractor Is Wrong (and What It’s Testing)
B. Flumazenil
Why it’s tempting: patient is altered; you’re thinking “reverse sedatives.”
Why it’s wrong: This patient is not sedated—he’s dangerously overstimulated.
High-yield: Flumazenil is risky because it can precipitate seizures, especially in:
- Chronic benzodiazepine users (withdrawal seizures)
- Mixed overdoses with pro-convulsant agents (e.g., TCAs)
USMLE takeaway: In an unknown ingestion, flumazenil is rarely the move. For stimulant intoxication, it’s simply off-target.
C. Haloperidol as monotherapy
Why it’s tempting: patient has psychosis and agitation.
Why it’s wrong: Antipsychotics can be adjuncts, but benzodiazepines are first-line.
What the test is getting at:
- Stimulant intoxication is a toxicologic emergency, not just “acute psychosis.”
- Haloperidol can:
- Lower seizure threshold (bad when stimulants increase seizure risk)
- Prolong QT (risk with tachycardia/electrolyte derangements)
- Potentially worsen thermoregulation in severe hyperthermia
Better framing: Use benzos first; consider an antipsychotic if agitation/psychosis persists after adequate sedation and vitals stabilize.
D. Propranolol
Why it’s tempting: hypertension + tachycardia = “give a beta-blocker.”
Why it’s wrong (especially for cocaine): risk of unopposed alpha stimulation → worsening vasoconstriction and hypertension/coronary vasospasm.
USMLE nuance:
- Classic teaching: avoid pure beta-blockers in cocaine intoxication.
- If a beta-blocker is needed (rare, specialist-guided), mixed alpha/beta like labetalol is sometimes used—but first-line remains benzodiazepines and vasodilators depending on the scenario.
Cocaine chest pain algorithm memory hook:
- Benzos + nitrates early
- Avoid propranolol
E. Naloxone
Why it’s tempting: altered patient in the ED → “opioid reversal.”
Why it’s wrong: Opioid overdose is the opposite toxidrome:
- Miosis, respiratory depression, bradycardia, hypothermia
- This patient has mydriasis, tachypnea, agitation, hyperthermia
USMLE twist: Sometimes patients use “speedballs” (cocaine + opioids), but you treat what’s killing them right now. If respiratory depression is present, naloxone matters. Here, the immediate threat is sympathomimetic toxicity → treat with benzodiazepines and cooling.
Rapid “Stimulant Intoxication” Recognition Table
| Feature | Stimulant intoxication (cocaine/amphetamines) | Opioid intoxication | Alcohol withdrawal | Serotonin syndrome |
|---|---|---|---|---|
| Pupils | Mydriasis | Miosis | Normal | Mydriasis |
| Skin | Diaphoretic | Often normal/cool | Diaphoretic | Diaphoretic |
| Vitals | ↑HR, ↑BP, ↑T | ↓RR, ↓HR, ↓T | ↑HR, ↑BP, ↑T | ↑HR, ↑BP, ↑T |
| Neuro | Agitation, seizures possible | CNS/resp depression | Tremor, seizures, hallucinosis | Hyperreflexia, clonus |
| First-line | Benzodiazepines + cooling | Naloxone | Benzodiazepines | Stop agent, benzos, cyproheptadine |
Step-Style High-Yield Pearls (Straight to Points)
- First-line for stimulant intoxication agitation/HTN/tachycardia: benzodiazepines.
- Hyperthermia kills: treat aggressively with sedation + cooling; consider rhabdo (check CK, renal function).
- Cocaine can cause MI via coronary vasospasm even in young people; treat chest pain with benzos and nitrates.
- Avoid pure beta-blockers in cocaine intoxication (classic “unopposed alpha” board concept).
- Stimulant withdrawal is not typically medically dangerous: think fatigue, depression, hypersomnia, increased appetite (contrast with alcohol/benzo withdrawal which can be fatal).
One-Liner to Remember
If the patient is “amped, agitated, and autonomic,” your first move is almost always: benzos + cool them down—then worry about the rest.