Therapeutic effect and safety of increasing doses of risperidone (R 64766) in psychotic patients

Risperidone (R 64766) was administered during 4 weeks in increasing doses to 17 psychotic patients, to evaluate the hematological and cardiovascular safety, the therapeutic effect, side effects, effects upon endocrinological parameters and the pharmacokinetic profile. Following a placebo wash-out period of 1 week, the initial dose was 10 mg daily, increasing with 5 mg per week until the maximal dose of 25 mg daily was reached during the 4th week of treatment. Doses up to 20 mg daily resulted in a significant improvement of the total BPRS score and of the different BPRS factor scores; with higher doses, no further clinical benefit was achieved except for the hostility and anxietydepression factor, while sedation became more prominent. No increase of extrapyramidal symptoms wasnoticed. Except for the sedation observed with higher doses, risperidone was well tolerated. No clinically relevant effects on cardiovascular and ECG parameters were noticed, and except for a slight increase of aspartate aminotransferase and alanine aminotransferase in one patient, no laboratory abnormalities were observed. Prolactin showed an expected increase, while the other endocrinological parameters revealed no changes. Risperidone had a linear pharmacokinetic profile.