Patients' attitudes towards generic substitution of oral atypical antipsychotics: a questionnaire-based survey in a hypothetical pharmacy setting

Abstract

Background: Generic atypical antipsychotics in tablet form differ in name, appearance and packaging from the innovator brand antipsychotics. These differences might cause anxiety, confusion and misperceptions in some ambulant patients with psychoses/schizophrenia, especially if the brand atypical antipsychotic is substituted in the pharmacy without the acknowledgement of the patient and treating psychiatrist. Furthermore, generic substitution of branded oral atypical antipsychotics in the pharmacy might cause nonadherence and potentially lead to suboptimal treatment outcomes if patients perceive the medicines to be clinically different.

Objective: To determine the attitudes of patients with psychoses/schizophrenia towards generic substitution of oral atypical antipsychotics in a pharmacy setting.

Methods: A total of 106 ambulant patients with psychoses/schizophrenia currently taking an oral atypical antipsychotic (risperidone [Risperdal], olanzapine [Zyprexa], quetiapine [Seroquel] or aripiprazole [Abilify]) were confronted with generic substitution in a hypothetical pharmacy setting.Two conditions were used: one granting patients a short explanation about the substitution, and one without explanation. Patients' attitudes towards the generic substitution were assessed using a combined quantitative and qualitative design.

Results: Of the respondents, 73% stated that they would be unlikely to take a generic antipsychotic if their pharmacist were to substitute it. Providing patients with a short explanation had a significantly positive effect on their intention to take a generic version; however, overall, the patients' intention to take the generic antipsychotic lay well below a neutral midpoint.

Conclusion: Patients with psychoses/schizophrenia using atypical antipsychotics in tablet form perceive generic versions of their antipsychotics as being significantly different. This perceived difference lowers their intention of continuing to take the medication, thus possibly jeopardizing treatment outcome. Caution with the generic substitution of atypical antipsychotics in the pharmacy is therefore recommended. Generic substitution should take place only with the knowledge and agreement of the psychiatrist and the patient.