A LOADING-DOSE STRATEGY FOR CONVERTING FROM ORAL TO DEPOT HALOPERIDOL

Objective: The authors' aim was to evaluate the safety and efficacy of a loading-dose regimen for initiating use of a depot medication, halo peridol decanoate, with patients who had been maintained on oral halop eridol. Patients were given a loading dose of about 20 times their ora l maintenance dose in divided injections during the first two weeks of conversion to depot medication. The dose of haloperidol decanoate was gradually reduced, dropping to about ten times the oral dose in the t hird and fourth months. No supplemental oral medication was used. Meth ods: Haloperidol decanoate was initiated using the loading-dose regime n in 16 chronically ill patients. Lower initial doses of haloperidol d ecanoate were used in two Other groups of patients, one that received supplemental oral haloperidol and one that did not. Plasma levels of h aloperidol, severity of illness, and side effects were monitored from baseline to 5 6 days after the beginning of depot therapy. Results: Pa tients who received the loading-dose regimen showed statistically sign ificant clinical improvement and reduced side effects over baseline by the 28th day. The second group of patients also maintained therapeuti c response but improved no further. The third group relapsed during th e first month and were returned to a regimen of oral haloperidol by th e second month. Conclusions: A loading-dose regimen for initiating tre atment with haloperidol decanoate is safe and effective and can be use ful in a clinical setting.