The word neuroleptic originates from the Greek word lepsis ("seizure" or "fit"). Antipsychotics (aka neuroleptics or tranquilizers) were investigate by the anesthesiologists De Castro and Mundeleer who coined the term neuroleptanalgesia, an anesthetic process that involves combining a major neuroleptic tranquilizer/antipsychotic (typically the potent D2 receptor antagonist droperidol) and the potent opioid analgesic fentanyl to produce a detached, pain-free state. Neuroleptanalgesia results in amnesia among some, but not all, patients.