Which of the following substances is classified as a narcotic?

Codeine is classified as a narcotic because it is an opioid that acts on the central nervous system to relieve pain. Narcotics, also known as opioids, are substances that can induce sleep or relieve pain but may also have the potential for addiction and abuse. They work by binding to specific receptors in the brain and spinal cord to block pain signals.

In contrast, the other substances listed have different classifications and properties. Aspirin is an analgesic and anti-inflammatory medication but does not fall under the narcotic category. Ativan, while it is a sedative that works on the central nervous system, is classified as a benzodiazepine rather than a narcotic. Tylenol, or acetaminophen, serves as an analgesic and antipyretic, but it is not considered a narcotic or an opioid. Understanding these classifications is essential in recognizing the effects, risks, and therapeutic uses of various medications in medical practice.