Which of the following is classified as a narcotic analgesic?

Narcotic analgesics, also known as opioids, are medications used to manage moderate to severe pain. They work by binding to specific receptors in the central nervous system, which reduces the perception of pain. Demerol, or meperidine, falls into this category as it is an opioid analgesic commonly prescribed to relieve pain.

In contrast, aspirin and ibuprofen are nonsteroidal anti-inflammatory drugs (NSAIDs) that provide pain relief by reducing inflammation and lowering fever, but they do not possess the narcotic effects associated with opioids. Paracetamol, known as acetaminophen in some regions, is an analgesic and antipyretic but does not qualify as a narcotic analgesic either. It acts differently and is typically used for mild to moderate pain relief. Therefore, Demerol is the only option listed that meets the criteria for classification as a narcotic analgesic.