I'm not seeing much on the web about Chlorprothixen and alcohol. Is there a pharmacist around that might be able to give you more info? Maybe double-check the insert you got with the drug to see if it mentions anything about it?
EDIT:
Here's something:
http://www.medicine-fast.com/product/Ch ... 30-tablets"The doctor will consider very carefully the application of this product in patients suffering from epilepsy, parkinsonism, mental retardation, alcoholism or abusing drugs with sedative (suppressing) effect on the CNS (central nervous system), cardiac disorders, severe liver and kidney diseases, disorders haemopoiesis, pulmonary disease, prostatic hypertrophy, glaucoma, myasthenia gravis, diabetes mellitus, in patients exposed to extreme / extreme temperatures and in the elderly."
Yeah, probably best to talk to your doctor about it, or at least a pharmacist.