Pinpoint pupils and respiratory depression are characteristic of which toxidrome?

• A. Opioid Toxidrome
• B. Cholinergic Toxidrome
• C. Anticholinergic Toxidrome
• D. Sympathomimetic

Answer: (A)

Pinpoint pupils with respiratory depression point most strongly to opioid toxicity. Opioids activate mu receptors in the brainstem, dampening the respiratory drive to CO2 and causing slow, shallow breathing. They also cause miosis through increased parasympathetic activity to the pupil, producing the classic “pinpoint” look.

Other toxidromes can have small pupils, but they come with different patterns. Cholinergic toxicity often includes excessive secretions, bradycardia, diarrhea, and bronchorrhea in addition to miosis. Anticholinergic toxicity causes dilated pupils and dry, hot skin with agitation. Sympathomimetic toxicity typically presents with dilated pupils, hypertension, tachycardia, and diaphoresis, without the characteristic respiratory suppression seen with opioids.

In summary, the combination of pinpoint pupils and respiratory depression is most characteristic of an opioid toxidrome.