Time-dependent effects of phenothiazines on dopamine turnover in psychiatric patients

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Science  31 Oct 1975:
Vol. 190, Issue 4213, pp. 488-489
DOI: 10.1126/science.1166321


Psychiatric patients studied early during treatment with chlorpromazine and thioridazine demonstrated elevated probenecid-induced accumulations of homovanillic acid, a major dopamine metabolite, in cerebrospinal fluid. In those studied after longer periods of treatment with phenothiazines, homovanillic acid values were not elevated. This suggests that there are time-dependent effects of phenothiazines on dopamine turn-over that may be relevant to the time course of antipsychotic efficacy.