Side effects related to potentially inappropriate medications in elderly psychiatric patients under everyday pharmacotherapy.

ABSTRACT

PURPOSE: Potentially inappropriate medication (PIM) is suggested to give rise to adverse drug events. To study this suggestion for elderly psychiatric patients, an observational analysis related prescription of PRISCUS PIMs and drug-induced side effects in old aged (≥65 years) psychiatric inpatients and outpatients under conditions of everyday pharmacotherapy. METHODS: Request forms from a therapeutic drug monitoring (TDM) survey and medical files were screened for medication to identify PIMs of the PRISCUS list and assessed using the Udvalg for Kliniske Undersøgelser (UKU) side effect rating scale. RESULTS: From 914 TDM request forms, data were available for 168 patients (64.3 % female). Patients (mean ± SD age 73.0 ± 5.5 years) received by mean 6.4 ± 3.9 drugs per day. More than half of them (53.0 %, n = 89) had at least one PIM, inpatients 0.9 ± 0.8 and outpatients 0.5 ± 0.7. Predominant PIMs were hypnotic drugs (69 %) in inpatients and antipsychotic drugs (35.6 %) in outpatients. The number of PIMs correlated with the total number of drugs administered per day (Spearman correlation coefficient 0.225, p < 0.01, CI 95 %). Side effects were documented for 106 patients (63 %). Severity of side effects did not correlate significantly (p > 0.05) with number of PIMs. However, only 6 of 77 patients who took no PRISCUS PIMs but 2 of 3 patients who took 3 PRISCUS PIMs exhibited severe side effects. CONCLUSIONS: Though the prevalence for PIMs and side effects was high in old aged psychiatric inpatients and outpatients, PIMs could not be identified as major determinants of overall unwanted side effects. Nevertheless, prescription of PIMs should be minimized, especially of hypnotic drugs, to improve safety.