Clinical outcomes following switching antipsychotic treatment due to market withdrawal: a retrospective naturalistic cohort study of pipotiazine palmitate injection (Piportil Depot) discontinuation, subsequent acute care use and effectiveness of medication to which patients switched.

Introduction: Pipotiazine palmitate depot injection (Piportil) was withdrawn from the UK marketplace in 2015. Few studies exist on the clinical impact of such market withdrawal. We aimed to identify a cohort of patients switching from pipotiazine following this withdrawal and explore factors associated with effectiveness of the medication switched to and subsequent acute service use.

Methods: A naturalistic retrospective cohort study was conducted in Sussex, United Kingdom. Those discontinuing pipotiazine solely due to market withdrawal were identified from electronic patient database and manual searching. Multivariate logistic regression analyses and survival analyses were performed to explore associations between available baseline variables and dichotomous all-cause discontinuation of the next prescribed medication and admission to acute mental health services over the subsequent year.

Results: Of 205 patients identified as receiving pipotiazine in October 2014, 137 switched from this due to market withdrawal. Over the subsequent year, 31.5% discontinued the medication to which they were switched and 19% required acute care. Drug class switched to (typical depot vs atypical long acting injection (LAI) vs atypical oral) had no significant association with discontinuation. Switch to atypical LAI was significantly associated with acute care in comparison to typical depot. Those with a schizophrenia diagnosis were significantly less likely to discontinue switched medication or to receive acute care in comparison to those with schizoaffective disorder. Women were significantly more likely to discontinue switched medication than men. Of those requiring acute care, only 38% had required this in the previous 2 years.

Conclusions: Antipsychotic market withdrawal has demonstrable negative clinical implications and requires careful clinical management. Increased acute care rates in those receiving an atypical LAI versus a typical depot following pipotiazine suggests lower effectiveness or possible withdrawal effects. No significant difference between depots, LAIs and oral medications on discontinuation supports the importance of a collaborative, fully informed approach when deciding next treatment options.