What is the principal manifestation of opioid overdose?

What is the principal manifestation of opioid overdose?

• A. Ventilatory depression.
• B. Hypotension.
• C. Pupils symmetric and miotic; mydriasis may occur with severe hypoxemia.
• D. Pulmonary edema.

Answer: (C)

Opioids act on mu receptors to depress the central nervous system, and a hallmark clinical sign of overdose is pinpoint, or miotic, pupils. This occurs because opioid stimulation increases parasympathetic outflow to the iris sphincter, producing small, symmetric pupils. While respiratory depression is the most dangerous and common physiologic effect driving risk, the presence of constricted pupils is the most characteristic and rapid clue to opioid overdose. It’s worth noting that in severe hypoxemia, pupils can become dilated (mydriasis), but this is a later, non-typical change; the classic presentation remains pinpoint pupils.

Opioids act on mu receptors to depress the central nervous system, and a hallmark clinical sign of overdose is pinpoint, or miotic, pupils. This occurs because opioid stimulation increases parasympathetic outflow to the iris sphincter, producing small, symmetric pupils. While respiratory depression is the most dangerous and common physiologic effect driving risk, the presence of constricted pupils is the most characteristic and rapid clue to opioid overdose. It’s worth noting that in severe hypoxemia, pupils can become dilated (mydriasis), but this is a later, non-typical change; the classic presentation remains pinpoint pupils.