A 28-year-old African American male with a history of
schizophrenia was hospitalized 22 days prior to the current admission for an episode of
olanzapine-induced NMS. The patient was discharged from our hospital to an outside psychiatric facility. At this facility, the patient developed
nausea and was given 2 doses (unknown amount and route) of
prochlorperazine. Over the next 24 hours, the patient exhibited signs and symptoms of NMS including
fever, agitation, and
muscle rigidity. He was transported to the emergency department and became increasingly agitated. Upon admission, the patient was hyperthermic (rectal temperature 39 °C) and tachycardic (heart rate 138 beats/min), with an elevated white blood cell count of 13.5 × 10(3)/μL,
creatine kinase 431 units/L, serum
sodium 150 mEq/L, blood
urea nitrogen 25 mg/dL, and
creatinine 1.1 mg/dL. A diagnosis of NMS was speculated and infectious causes were excluded. The patient was treated with aggressive fluid
resuscitation and rapid cooling measures, as well as
bromocriptine and
lorazepam. Cooling measures were used for 48 hours, during which time the
creatine kinase, white blood cell count,
sodium, blood
urea nitrogen, and
creatinine gradually normalized. The patient was discharged to a psychiatry facility with a treatment regimen of
oxcarbazepine 600 mg twice daily,
lorazepam 2 mg 3 times daily, and
clozapine 25 mg at bedtime, which was titrated over 2 months to 200 mg twice daily. There have been no further occurrences of NMS.
DISCUSSION: The patient had all of the major characteristics of NMS with no other likely causative factors that may have contributed to his illness. Use of the Naranjo probability scale suggested that NMS was probably related to
prochlorperazine. This case highlights the potential increased risk with the use of
prochlorperazine in a patient with a history of
olanzapine-induced NMS.
CONCLUSIONS: