neuroleptanalgesia /-lept′anəljē″zē·ə/ [Gk, neuron + lepsis, seizure, a + algos, without pain] , (Obsolete) a form of sedation and analgesia once used that involved the concurrent administration of a neuroleptic such as droperidol and an analgesic such as fentanyl. Anxiety, motor activity, and sensitivity to painful stimuli were reduced; the person was quiet and indifferent to surroundings and was able to respond to commands. If nitrous oxide with oxygen was also administered, neuroleptanalgesia could be converted to neuroleptanesthesia. Adverse reactions, such as a prolonged QT interval produced by a large dose of droperidol, caused this method to be abandoned.