Discontinuation of two-injection aripiprazole long-acting regimen: a pharmacological and psychopathological analysis

Objectives

A double-injection regimen for initiating aripiprazole long-acting injection (ALAI) has been approved for use based only on a pharmacokinetic modelling study. This regimen involves administering two injections of ALAI plus a single oral dose of aripiprazole, as opposed to the original regimen which called for four weeks of oral treatment with one injection. To date, there have been no studies evaluating the relative effectiveness of the double injection regimen compared with a single ALAI dose start.

Methods

We carried out a non-interventional, year-long observational study of the single and double-injection regimen for ALAI initiation. We analysed time to discontinuation with both regimens and noted reasons for discontinuation.

Results

Data were collected on 173 patients initiated on ALAI (43 double-injection, 130 single-injection initiation). Median time to discontinuation of ALAI was 111 days (95%CI 56 – 254) in the double-injection group, and 272 days (95%CI 202 - > 365) in the single-injection group (p = 0.004). For inpatients (n = 118) initiated on ALAI, median time to discharge was 14 days in the double-injection group, and 21 days in the single-injection group. There was no clear difference in discontinuations due to adverse effects.

Conclusion

Patients initiated with a double-injection regimen discontinued treatment earlier and to a greater extent than those given single-injection initiation. It is not clear that this difference relates to the regimens themselves or the reasons for choosing the particular regimen (e.g. prior non-compliance; reluctance to accept treatment).