Neuroleptic malignant syndrome after neuroleptic discontinuation.

1. Neuroleptic withdrawal can cause autonomic and behavioral symptoms (nausea, vomiting, diarrhea, diaphoresis, myalgia, anxiety, restlessness) and movement disorders (withdrawal emergent parkinsonism, withdrawal dyskinesia, covert dyskinesia). 2. Neuroleptic malignant syndrome (NMS) is a rare but extremely severe adverse reaction to neuroleptic drugs characterized by extrapyramidal and autonomic symptoms, altered level of consciousness and abnormal laboratory findings. 3. Withdrawal neuroleptic malignant syndrome, though an even rarer condition (only 7 cases reported to date), should alert to consider the possibility that abrupt neuroleptic discontinuation can be complicated by NMS. 4. The pathophysiology of withdrawal medical symptoms may be related to a cholinergic rebound; withdrawal neuroleptic malignant syndrome may be attributed to an "imbalance" in the dopaminergic system. 5. The authors report two cases of NMS precipitated by the abrupt withdrawal of neuroleptic drugs.