The hydrochloride salt of a synthetic piperidine ester with opioid analgesic activity. Meperidine mimics the actions of endogenous neuropeptides via opioid receptors such as the mu-opiiod receptor, thereby producing characteristic morphine-like effects including analgesia, euphoria, sedation, respiratory depression, miosis, bradycardia and physical dependence. or A drug used to treat moderate to severe pain. It binds to opioid receptors in the central nervous system. Meperidine hydrochloride is a type of analgesic agent and a type of opioid. Also called Demerol.