Thyrotropin-releasing hormone is an endogenous tripeptide with endocrine-independent neurophysiologic properties that may be relevant to affective or seizure disorders. We studied the effect of carbamazepine, which has both mood-stabilizing and anticonvulsant properties, on cerebrospinal fluid thyrotropin-releasing hormone levels in affectively ill patients.
Paired cerebrospinal fluid samples were collected from nine inpatients with mood disorders, both while medication 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.
Carbamazepine treatment was consistently and significantly associated with increased cerebrospinal fluid thyrotropin-releasing hormone levels (P<.0001).
As carbamazepine-induced increases in thyrotropin-releasing hormone levels could be relevant to either its psychotropic or anticonvulsant properties, further clinical and preclinical investigation of this finding appears indicated.