Possible Interaction: Chlorpromazine and Tryptophan

“4 Chlorpromazine inhibits hyperactivity caused by tryptophan or 5‐MeODMT after monoamine oxidase inhibition either by competition with 5‐HT or 5‐MeODMT, respectively, at receptor sites or by physiological antagonism.”

“Clozapine, but not chlorpromazine , haloperidol, thioridazine, or loxapine, increases the concentrations of tryptophan , serotonin, and 5-hydroxyindoleacetic acid in the brain of the rat.”

“We suggest that it is through this pathway that CPZ might increase and HP might decrease brain tryptophan and thereby lead to opposite changes in brain 5-HT content.”

“Only chlorpromazine , when given for 4 days, enhanced the hyperactivity response following tranylcypromine and L-tryptophan , probably because the drug also blocks 5-HT receptors.”

“The mean 8 h and 16 h cortisol levels were 70% higher compared to levels obtained at 24 h. Chronic administration of haloperidol and chlorpromazine led to significant increase in the plasma tryptophan (P<0.001 andP<0.1, respectively) compared to saline-treated rabbits.”

“It has been shown previously (Bender, 1976~) that administration of chlorpromazine to rats results in a decrease in the total serum tryptophan concentration, and a decrease in the proportion of tryptophan bound to serum albumin, so that the concentration of diffusible tryptophan remains at or above the control value.”

“Table 2 shows that chlorpromazine , chlorprothixene and thioridazine led to a significant increase in the apparent concentration of tryptophan in the sample used.”

“Clozapine, but not chlorpromazine , haloperidol, thioridazine, or loxapine, increases the concentrations of tryptophan , serotonin, and 5-hydroxyindoleacetic acid in the brain of the rat.”