Drug holidays and serum haloperidol levels in schizophrenic patients

Chronic hospitalized schizophrenic patients receiving haloperidol were placed on drug holidays for 2 days. Serum haloperidol levels in these patients decreased to about 60% of the levels seen just prior to the usual morning dosing during the drug holiday. Control subjects not given a drug holiday showed stable day-to-day serum haloperidol levels. The small drop in serum haloperidol blood levels may relate to the lack of relapse observed in such patients.