Which of the following is a semi-synthetic opiate?

• A. Heroin
• B. Morphine
• C. Methadone
• D. Fentanyl

Answer: (A)

Semi-synthetic opiates are made by chemically modifying a natural opiate such as morphine to enhance certain properties. Heroin fits this by being diacetylmorphine, which is morphine with two acetyl groups added. This modification increases its lipid solubility, so it crosses the blood–brain barrier rapidly and produces a faster, more intense effect, which contributes to its high abuse potential. Morphine is a natural opiate, not semi-synthetic. Methadone and fentanyl are fully synthetic opioids created without starting from morphine, so they’re not semi-synthetic.