APEA Neurology Practice Test

Pupil constriction with drowsiness and slurred speech points most strongly to opioid toxicity. Opioids activate µ receptors in the brainstem, which slows respiration and increases parasympathetic effects, producing pinpoint pupils, sedation, and slowed speech. Low blood pressure can accompany overdose as respiratory depression and vasodilation reduce perfusion.

Amphetamine overdose would typically cause dilated pupils, hyperactivity, agitation, and hypertension rather than sedation. Benzodiazepine overdose can cause slurred speech and drowsiness, but pupils are usually not constricted. Marijuana use can cause drowsiness, but pupil constriction is not a defining feature and signs differ.

Thus, the constellation of pinpoint pupils plus sedation best fits opioid intoxication.