A systematic review and meta-analysis of the effect of depot antipsychotic frequency on compliance and outcome.

BACKGROUND

Depot antipsychotics are commonly used to improve adherence and clinical outcomes such as relapse and readmission. Dosing regimens vary but are commonly two- and four-weekly. To date, the effect of administration at two-weekly or four-weekly intervals on outcome has not been examined in a meta-analysis.

AIMS: A systematic review and meta-analysis on whether the frequency of depot antipsychotic administration (e.g., two- vs four-weekly) makes any difference to compliance and outcome.

METHODS

A systematic search of Medline, EMBASE and PsycInfo for RCTs that compared the frequency of depot administration (e.g., two- vs four-weekly) for an equivalent dose. Outcomes were compliance, psychiatric symptomatology, quality of life, adverse drug reactions (ADRs), patient preference, admission rates, bed-days and costs.

RESULTS

Seven studies from eight papers (n=3994) were found covering olanzapine, paliperidone, risperidone, haloperidol and fluphenazine enanthate/decanoate with follow-up of up to one year. Meta-analyses were possible for psychotic symptoms and ADRs. There were no differences in psychotic symptoms or quality of life between two- and four-weekly doses. Health service use was not reported. For ADRs, the only significant difference detected was that two-weekly injections were less likely to lead to site pain (RR 0.16, 95% CI 0.07-0.38; 2 studies n=1667). There were no differences in other ADRs.

CONCLUSIONS

There were surprisingly little data on the effect of dosing frequency for an equivalent dose on clinical outcomes. There is a need for long-term studies of a wide range of outcomes including cost-effectiveness. Claims for advantages of new preparations over others require careful evaluation.