CARBAMAZEPINE INCREASES CEREBROSPINAL-FLUID THYROTROPIN-RELEASING-HORMONE LEVELS IN AFFECTIVELY ILL PATIENTS

Background: Thyrotropin-releasing hormone is an endogenous tripeptide with endocrine-independent neurophysiologic properties that may be rel evant to affective or seizure disorders. We studied the effect of carb amazepine, which has both mood-stabilizing and anticonvulsant properti es, on cerebrospinal fluid thyrotropin-releasing hormone levels in aff ectively ill patients. Method: Paired cerebrospinal fluid samples were collected from nine inpatients with mood disorders, both while medica tion free and while taking carbamazepine for an average of longer than 1 month at 950 mg/d, achieving blood levels of 8.8 mg/L. Results: Car bamazepine treatment was consistently and significantly associated wit h increased cerebrospinal fluid thyrotropin-releasing hormone levels ( P<.0001). Conclusion: As carbamazepine-induced increases in thyrotropi n-releasing hormone levels could be relevant to either its psychotropi c or anticonvulsant properties, further clinical and preclinical inves tigation of this finding appears indicated.