Establishing a dose–response relationship for haloperidol decanoate

Abstract

Aims and MethodThe aim of this literature analysis was to establish the range of doses of haloperidol decanoate effective in preventing relapse in schizophrenia. Studies reporting relapse rates in patients treated for longer than 6 months were included. Relapse rate was then plotted against dose or log dose to allow drawing of dose–response curves.ResultsFifteen publications reporting 13 individual studies were identified. of these, 6 studies met inclusion criteria and were analysed. Dose–response curves indicated limited effect at 25 mg/4 weeks but near maximal effect at doses of 50 mg/4 weeks. There was no clear evidence that increasing the dose above 100 mg/4 weeks provided additional benefit in preventing relapse.Clinical ImplicationsThe recommended dose range for haloperidol decanoate (50–300 mg/ 4 weeks) does not reflect the findings of this study. Optimally effective doses appear to be around 50–100 mg/4 weeks. The use of doses above 100 mg/4 weeks is difficult to support given data available.