Effects of repeated drug holidays on serum haloperidol concentrations, psychiatric symptoms, and movement disorders in schizophrenic patients.

In a crossover experiment the authors investigated the effects of repeated weekly, 2-day, haloperidol drug holidays on serum haloperidol concentrations, mental status, and neuroleptic-induced movement disorders in seven chronic schizophrenic patients. Haloperidol concentrations decreased about 64% during the initial 36 hours of drug holiday and subsequently increased slightly during the next 24 hours of drug holiday. Two-day weekly drug holidays for 6 weeks resulted in an average reduction of 25% in serum haloperidol concentrations at all drug holiday points. Mental status and movement disorders scores, rated by observers blind to the drug-holiday condition, were not significantly affected by drug holidays.