Which substance is commonly classified as a narcotic?

Heroin is classified as a narcotic because it is an opiate, which is derived from the opium poppy. Narcotics primarily refer to substances that have sedative and pain-relieving properties. Heroin acts directly on the brain’s opioid receptors, leading to feelings of euphoria and pain relief, which is a defining characteristic of narcotic substances. The classification of heroin as a narcotic also relates to its potential for addiction and the risk of misuse, distinguishing it from other substances listed in the options.

In contrast, ketamine is primarily used as an anesthetic and has dissociative properties, MDMA, commonly known as ecstasy, is primarily classified as a stimulant and empathogen, and peyote is a hallucinogenic substance. These classifications help convey the effects and potential risks of different substances in relation to narcotic use and regulation.