Phendimetrazine, a Schedule III sympathomimetic stimulant and appetite suppressant formerly marketed as Bontril, Plegine, and Prelu-2 among others, is prescribed for short-term obesity management and monitored clinically for accurate therapeutic compliance and misuse detection. In forensic toxicology, accurate identification of phendimetrazine and its primary metabolite phenmetrazine is critical in workplace drug testing, postmortem investigations, and drug seizure analysis. LC-MS/MS and GC-MS are the standard analytical techniques, though co-elution with structurally similar amphetamine-class compounds demands rigorously characterized reference materials for accurate quantitation.