Chlorpromazine Amfetamines

Chlorpromazine has sometimes been used to treat amfetamine psychosis, for example due to acute poisoning in children who did not respond to barbiturates (14). 

A 38-year-old Caucasian woman, who had taken heroin vapor 2 weeks before, developed confusion, ataxia, and urinary incontinence. She was afebrile and spoke with a slow low-volume monotonous voice. She had marked truncal ataxia with absent postural reflexes, cogwheel rigidity in her limbs, and marked bradykine-sia. She had used non-prescription amfetamine up to 4 g/day intermittently for 8 years. After a bout of depression, she came under the care of a psychiatrist and stopped taking amfetamine after she was given chlorpromazine and diazepam. She then started using... 

The appetite suppressant and other effects of amfetamines, chlo-rphentermine and phenmetrazine are opposed by chlorpro-mazine. It seems possible that other phenothiazine will interact similarly. The antipsychotic effects of chlorpromazine can be opposed by dexamfetamine. 

Not understood. It is known that chlorpromazine can inhibit adrenergic and dopaminergic activity, which could explain some part of the antagonism of the amfetamines, the euphoriant effects of which are said to be mediated by central dopamine receptors. 

Established interactions. These reports suggest that it is not beneficial to attempt to treat patients taking chlorpromazine with amfetamines, such as dexamfetamine, or other central stimulants such as phenmetrazine. In one study, thioridazine also appeared to interact. However, it is not clear whether this interaction takes place with antipsychotics other than chlorpromazine, but it seems possible with the phenothiazines, especially if the suggested mechanism is correct. Note that central stimulants are no longer recommended for the treatment of obesity. 

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