Which drug class includes morphine, codeine, heroin, oxycodone and can cause coma and severe respiratory depression?

• A. Stimulants
• B. Inhalants
• C. Barbiturates
• D. Narcotics

Answer: (D)

The drugs listed—morphine, codeine, heroin, and oxycodone—are opioids, commonly called narcotics. They activate mu opioid receptors in the brain and spinal cord, producing analgesia and sedation. A dangerous effect of this class is respiratory depression: the brainstem’s drive to breathe in response to carbon dioxide is suppressed, so breathing becomes slow and shallow and can stop entirely in overdose, leading to coma. That’s why this drug class best fits the description.

Stimulants increase alertness and energy and don’t share this mechanism. Inhalants affect the CNS in different ways and aren’t defined by this opioid list. Barbiturates are another type of CNS depressant that can cause coma and respiratory depression, but they are a separate class from these opioids. The key point is that these substances are opioids, i.e., narcotics, with the highest risk of coma and severe respiratory depression in overdose.