A 40-year-old patient with a history of chronic back pain is found unresponsive with shallow breathing and constricted pupils. Which of the following is the most likely substance involved?

Explanation

The classic triad of opioid overdose includes miosis (constricted or pinpoint pupils), respiratory depression (shallow breathing), and altered mental status (unresponsiveness). Cocaine and amphetamines are stimulants and would typically cause mydriasis (dilated pupils), tachycardia, and agitation. Alcohol overdose can cause respiratory depression and unresponsiveness, but typically not pinpoint pupils.