Choosing an Optimal Antipsychotic Dose for Relapse Prevention

Taipale et al.1 (this issue) investigated optimal antipsychotic dose for the maintenance treatment of schizophrenia by linking the Hospital Discharge registry of Finland with the prescription register 1995 to 2017 from which they estimated dose for each prescribing period classified in the WHO Defined Daily Dose (DDD) categories<0.6, 0.6 –0.9, 0.9–1.1, 1.1–1.4, 1.4–1.6, ≥1.6. The DDD was developed as a tool for drug utilization research that reflects common doses used to treat schizophrenia with 1 DDD unit being an average dose (eg, 10 mg olanzapine is 1 DDD unit, 0.6 DDD is 6 mg, 1.6 DDD is 16 mg). The DDD corresponds app roximately to efficacious doses found in short-term trials of schizophrenia.2 The analysis estimates the rate of relapse (using within-subject Cox regression) occurring at the various doses in DDD units. Relapse was defined as rehospitalization. Each analysis was restricted to patients who received just monotherapy with one of the 15 antipsychotics and had several relapses preceded by different maintenance doses. Compared to nonuse of antipsychotics within the same individual, 13 of the 15 antipsychotics investigated showed a U- or J-shaped dose –response curve usually with the best prevention of relapse at 0.9–1.1 DDD. The lowest preventive effect was seen at the highest dose (1.6 DDD or greater). An increase in relapses was also seen with the lowest dose (less than 0.6 DDD units) for some drugs.
Source: Schizophrenia Bulletin - Category: Psychiatry Source Type: research