LAUSR

Abstract Background Long-acting injectable (LAI) antipsychotics have been shown to reduce risk of relapse in people with psychosis. Second generation LAI antipsychotics such as paliperidone palmitate can have fewer side-effects and be better tolerated than first generation LAI antipsychotics. However, paliperidone palmitate is more expensive and there are few data comparing its effectiveness and tolerability with that of other LAI antipsychotics. We sought to address this issue by analysing a large electronic mental health case register. Methods The South London and Maudsley NHS Foundation Trust Biomedical Research Centre Case Register was used to obtain data about people who had started treatment with an LAI antipsychotic between April 1, 2011, and Jan 31, 2015. The number of days spent as a psychiatric inpatient and the number of admissions to a psychiatric hospital were analysed using multivariable regression with age, sex, ethnicity, marital status, diagnosis, and London borough of residence as covariates. Findings 1281 people had started treatment with LAI antipsychotics. The most frequently prescribed LAI was paliperidone palmitate (n=430, 33·6%) followed by zuclopenthixol decanoate (226, 17·6%), flupentixol decanoate (203, 15·9%), risperidone (160, 12·5%), pipotiazine palmitate (114, 8·9%), haloperidol (71, 5·5%), fluphenazine decanoate (36, 2·8%), aripiprazole (27, 2·1%), and olanzapine embonate (14, 1·1%). There were no significant differences between paliperidone and other LAI antipsychotics in the number of days as an inpatient (β coefficient 5·4 days, 95% CI −57·3 to 68·2) or number of hospital admissions after initiation of treatment (incidence rate ratio 1·07, 95% CI 0·62 to 1·83). Interpretation The absence of differences in hospital admission after initiation of LAI antipsychotics indicates that the effectiveness of the second generation LAI paliperidone palmitate was similar to that of other LAI antipsychotics. However, the discontinuation rate in the first year of treatment is lower for paliperidone palmitate (35%) than for other LAI antipsychotics suggesting that it is better tolerated. These findings merit consideration in relation to the choice of LAI antipsychotic to prescribe in people with psychotic disorders. Funding National Institute for Health Research, Medical Research Council.