Normeperidine hydrochloride (also known as norpethidine) is the primary metabolite of the opioid analgesic meperidine (pethidine). It is not used therapeutically due to its neuroexcitatory effects, including the potential to cause seizures and tremors. Instead, it serves as a reference standard in pharmaceutical research, toxicology studies, and analytical chemistry for monitoring meperidine metabolism and drug interactions. As a specialty chemical, it is employed in laboratory settings to investigate opioid pharmacokinetics and neurotoxicity.