The treatment of neuroleptic malignant syndrome using dantrolene sodium.

The use of dantrolene sodium (DS) in the treatment of neuroleptic malignant syndrome (NMS) was studied from the data of 21 cases of NMS, which satisfied the diagnostic criteria of Pope et al. The mean dosage of DS was 0.97+/-0.52 mg/kg per day and the mean duration of treatment was 8.3+/-5.3 days. It was confirmed that the mean duration of treatment with DS tended to be longer in the cases involving disturbance of consciousness. However, there were no significant differences in the duration of treatment or the mean daily dosage, in the cases without disturbance of consciousness regardless of any other complications and symptoms. Also, there were no significant differences in the mean duration of treatment using DS and the mean dosage of DS between five cases that were considered to be 'typical' and 16 cases that were considered to be 'incomplete'. In addition, the prognoses of these cases were good such that not even one death occurred. In 13 cases, the treatment of psychiatric symptoms with thioridazine was started without recurrence of NMS.