Which of the following is an example of an opioid?

Demerol, known generically as meperidine, is classified as an opioid analgesic. Opioids are substances that bind to the opioid receptors in the brain and spinal cord, producing effects such as pain relief, sedation, and euphoria. Demerol is specifically used for its pain-relieving properties in various medical settings, including postoperative analgesia.

The other medications listed are not opioids. Versed (midazolam) is a benzodiazepine used for sedation, anxiety relief, and amnesia. Flumazenil is a benzodiazepine antagonist that reverses the effects of benzodiazepines. Romazicon is a brand name for flumazenil. Neither of these have the pain-relieving properties typical of opioids. Understanding these classifications is crucial for healthcare professionals when selecting appropriate medications for pain management or sedation in surgical contexts.