Neuroleptic malignant syndrome.

NMS is a life-threatening, hyperpyrexic syndrome that follows the blockage of certain central dopaminergic receptor sites; it is commonly associated with the use of neuroleptic medications. Clinical signs usually include hyperthermia, altered mental status, muscle rigidity, and autonomic instability. Treatment is mainly supportive. Dopamine agonists and muscle relaxants are often used in therapy; however, their effectiveness has never been adequately determined in controlled studies.