Which of the following is NOT a semisynthetic opioid?

Meperidine is not classified as a semisynthetic opioid; rather, it is considered a fully synthetic opioid. It is synthesized from basic chemical compounds, which means it does not originate from opium or its natural derivatives. Semisynthetic opioids, on the other hand, are derived from naturally occurring opiates that have undergone chemical modifications to enhance their effectiveness or other properties.

Heroin, oxycodone, and hydromorphone all fall into the category of semisynthetic opioids. These substances are derived from morphine or codeine, which are natural opiates. Their chemical structure is altered to achieve specific pharmacological benefits, such as increased potency or improved pain relief profiles, distinguishing them clearly from synthetic opioids like meperidine. Understanding this classification is important in both pharmacology and the history of opioid usage, as it helps clarify the distinctions among different types of opioid medications.