A 19-year-old man is brought to the emergency department after being found by his roommate to have snorted cocaine several times in the past few days, the last time being 10 h previously. He was given a drug that sedated him, and he fell asleep. The drug that was used to counter this patient's apparent cocaine withdrawal was very likely which of the following?

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: Opium alkaloids are naturally derived from the opium poppy (Papaver somniferum). Morphine, the principal alkaloid, is a potent mu receptor agonist used for severe pain. Codeine, milder, acts as an analgesic and antitussive, also poppy-derived. Papaverine, a smooth muscle relaxant, is another natural alkaloid from opium, though less opioid-like. Meperidine (choice C) is a synthetic opioid, chemically distinct (a phenylpiperidine), developed as a pharmaceutical alternative for pain management, not extracted from opium. It mimics natural opioids via receptor agonism but isn't naturally occurring. This differentiation is essential in pharmacology to classify drugs by origin, impacting their regulation, synthesis, and clinical understanding. The question tests knowledge of natural versus synthetic opioids, crucial for historical context and therapeutic application.

Correct Answer: C

Rationale: Acute salicylate (aspirin) intoxication causes hyperpyrexia (choice A) from uncoupled oxidative phosphorylation, hyperpnoea (choice B) from respiratory center stimulation, and metabolic acidosis in children (choice D) from acid accumulation. Pinpoint pupils (choice C), or miosis, are absent; salicylates don't affect pupil size like opioids, which cause miosis via mu receptors. Salicylate toxicity may cause tinnitus or confusion, but pupil effects aren't typical. This exception distinguishes salicylate poisoning from opioid overdose, aiding differential diagnosis in toxicology.

Correct Answer: A

Rationale: L-DOPA (choice A) treats Parkinsonism by crossing the blood-brain barrier and converting to dopamine, replenishing deficient levels. a-Methyldopa (choice B) lowers blood pressure, not Parkinsonism. Haloperidol (choice C), a dopamine antagonist, worsens it. Physostigmine (choice D), a cholinesterase inhibitor, aids cognition, not movement. L-DOPA's role is central to Parkinson's management.