INCREASED PLATELET AGGREGATION IN PATIENTS RECEIVING CHLORPROMAZINE: RESPONSES TO 5‐HYDROXYTRYPTAMINE, DOPAMINE AND N‐DIMETHYL DOPAMINE

Abstract

1 Platelet aggregation responses to 5-HT, dopamine, N-dimethyl dopamine and adenosine diphosphate were compared in normal subjects and patients treated with chlorpromazine (CPZ) for longer than 6 months. 2 We confirmed our previous finding that 5-HT induced aggregation is enhanced in CPZ treated patients. 3 Increased aggregation responses were also observed with dopamine and N-dimethyl dopamine. 4 Quantitative comparisons of aggregation rates and total changes in optical density of platelet rich plasma relative to adenosine diphosphate showed significant increases with 5-HT, dopamine and N-dimethyl dopamine. 5 Implication of dopaminergic mechanisms in the central effects of phenothiazines suggests that changes in dopamine induced aggregation responses may be useful in attempting correlations of clinical and pharmacological effects.