Dear Editor,
We read with interest the recent audit by Kelly et al. on the favourable impact of local policy change on prescribing of multiple antipsychotic medications (Kelly et al. Reference Kelly, Kelly, Santlal and O’Ceallaigh2014). It has clearly confirmed that adoption of the new antipsychotic prescribing policy has resulted in a positive impact on prescribing multiple antipsychotics. The percentage of patients prescribed multiple antipsychotics has gone down significantly from 28% to 16% (significantly better than a reduction in prescribing multiple antipsychotics from 43% to 39% reported in a similar large-scale UK audit; Paton et al. Reference Paton, Barnes, Cavanagh, Taylor and Lelliott2008). The latter figure provided by Dr Kelly and his colleagues (i.e. 16%) is comparable with the 14.4% figure found in a survey of prescribing multiple antipsychotics for patients with schizophrenia in the United States (Edlinger et al. Reference Edlinger, Hausmann, Kemmler, Kurz, Kurzthaler, Walch, Walpoth and Fleischhacker2005) and the 15.9% figure reported in a similar English survey (Patel et al. Reference Patel, Bishara, Jayakumar, Zalewska, Shiers, Crawford and Cooper2014). A recent French study reported a staggering 49.3% rate of prescribing for multiple antipsychotics across all general hospitals in France (Bret et al. Reference Bret, Bret and Queuille2009).
However, in the reported results of Kelly et al.’s audit, we could not identify the route of administration of antipsychotics. Practically speaking, we do prescribe injectable long-acting antipsychotics to a large number of patients. According to National Institute for Health and Clinical Excellence (NICE) Guidance, long-acting antipsychotics should be monitored the same way like oral antipsychotic medications: ‘take into account the same criteria recommended for the use of oral antipsychotic medication, particularly in relation to the risks and benefits of the drug regimen’ (NICE, 2014). In Kelly et al.’s study, the proportion of patients on long-acting injectable antipsychotics was not provided. The only exclusion criterion was being on clozapine augmented with regularly prescribed antipsychotics. This led to exclusion of three patients.
Very little, if any, research has evaluated the rate of co-prescription of oral and depot antipsychotics. In 2002, in an investigation carried out by Tylor et al. (Reference Tylor, Mir and Mace2002), 15 patients were identified to be on combined depot and oral antipsychotics. A more recent audit identified 43 of patients on combined depot and oral antipsychotics; likely to be chlorpromazine or haloperidol prescribed for agitation or insomnia (Rajan & Clarke, Reference Rajan and Clarke2013).
Depot injections are licensed for treatment of psychotic disorders. There are eight depot preparations listed in the most recent BNF (The Joint Formulary Committee, 2014). A couple of difficulties may have led to under-investigation of depot preparation in the range of studies aimed at estimating the extent of antipsychotics polypharmacy. First, the slow-release nature of long-acting antipsychotics can make it hard to calculate the total daily antipsychotic dose percentage. Second, the section for prescribing the depot preparation in the medication kardex is often at the back of the chart or at the bottom of a page far away from the regular prescriptions section. This can lead to easy omission, specifically if it is not borne in mind while collecting the data on antipsychotic polypharmacy.
A particular clinical conundrum is when patients who are established on maintenance depot antipsychotics become acutely unwell. It is almost always tempting to commence some oral antipsychotic medication that is intended to control the acute episode of behavioural disturbance. Despite the intention to be prescribed for short-term use, patients often end up being on combined oral and depot antipsychotics. Do the authors agree that such episodic behavioural disturbances can be a major route to antipsychotic polypharmacy? Can they provide any guidance on how to manage such episodes without subjecting patients to the risk of exceeding the daily antipsychotic dose limit?
