A forensic laboratory receives urine from a driver suspected of heroin use two hours before testing. Morphine may arise from legitimate codeine medication, so to prove specifically that heroin was taken, the analyst must demonstrate which compound in urine?

• A Codeine
• B Noscapine
• C Morphine-3-glucuronide
• D 6-monoacetylmorphine ✓

Explanation

Heroin is rapidly deacetylated to 6-monoacetylmorphine (6-MAM), which is then converted to morphine. 6-MAM is unique to heroin metabolism because codeine is demethylated directly to morphine and never passes through 6-MAM. Detecting 6-MAM therefore proves heroin intake specifically, while morphine or its glucuronide alone cannot distinguish heroin use from codeine-containing cough preparations.

Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.