Do users of risperidone who switch brands because of generic reference pricing fare better or worse than non-switchers? A New Zealand natural experiment

Abstract

This study evaluated patient health outcomes and any impact on healthcare costs consequent to the implementation of generic reference-pricing of risperidone in New Zealand using national datasets. Reference pricing risperidone reduced the price of the originator brand by 50 % as well as overall expenditure on risperidone tablets. Half of all patients made a single switch to generic risperidone, with the remainder making multiple switches between brands. 1.5 % made a switch-back to the originator brand. No difference was found in use of healthcare services between switchers and non-switchers of the originator brand or versus the comparator group. This refutes the available literature on brand-to-generic and generic-to-generic switching.

An Evaluation of Health Service Impacts Consequent to Switching from Brand to Generic Venlafaxine in New Zealand under Conditions of Price Neutrality

“…The findings of this study are consistent with those of similar studies from New Zealand evaluating the effects of lamotrigine and risperidone brand switching where, despite patterns of multiple switches among patients, no adverse effects were evident [31,32]. Further reports related to venlafaxine include a report of therapeutic drug monitoring of venlafaxine in Germany among 35 patients that found no difference in serum concentrations between originator brand and generic formulations [33], and another bioavailability study among volunteers where no difference between originator and generic formulations was found [34].…”

Switching medication products during the treatment of psychiatric illness

“…In this retrospective database study, about 75% of reference risperidone users switched to one of the generic versions, and 1.5% switched back to the reference version; among those who switched, 50% remained with the same generic product, while the remainder made multiple between-product switches (40% made >2 switches, and 9% made >3 switches). Patterns of health care utilisation did not differ between switchers and nonswitchers during follow-up (Lessing et al, 2015a).…”

“…Switching patterns and clinical outcomes following the implementation of generic reference pricing for risperidone were evaluated in patients with schizophrenia in New Zealand who were receiving stable treatment with reference risperidone (Lessing, Ashton, & Davis, 2015a). In this retrospective database study, about 75% of reference risperidone users switched to one of the generic versions, and 1.5% switched back to the reference version; among those who switched, 50% remained with the same generic product, while the remainder made multiple between-product switches (40% made >2 switches, and 9% made >3 switches).…”

The impact on health outcome measures of switching to generic medicines consequent to reference pricing: the case of olanzapine in New Zealand

“…The rate of death following switching was not significantly different from death rates reported for New Zealanders with a diagnosis of a psychotic disorder, 28 or from adult users of risperidone in NZ. 29 Reviews that evaluate generic psychotropic medicines and the issue of switching are available in the literature; however, reports that extrapolate the effects of typical antipsychotics against the pharmacologically different atypical ones should be met with caution. 30,31 Little evidence is available for the relatively newer atypical antipsychotic medicines, such as olanzapine, and few published reports of olanzapine bioequivalence studies exist, aside from those conducted for product registration.…”