Impact of generic substitution practice on care of diabetic patients.

Background: Patients with chronic diseases like type II diabetes mellitus often have their prescriptions substituted with generic medicines in the course of care to save costs of medicines and to improve access. There is need to assess impact of this practice on patient care.

Objective: To assess patient's knowledge of generic substitution practice and its impact on patient care.

Setting: An outpatient diabetic clinic of a tertiary hospital in Nigeria.

Method: The study is a cross sectional survey of patients attending a diabetic clinic. A structured questionnaire was used to interview willing patients. A total of 120 patients were enrolled for the study, but only 102 responded (85 % overall response rate).

Main Outcome Measures: Patients' knowledge of generic substitution practice, patients' report of abstaining from drug use, experiences of more side effects and patients' confusion.

Results: Over half (57.8 %) of surveyed patients (n = 59) had noticed brand switches, out of which, 30.5 % experienced brand switches more than 3 times within a year. More than a third of the respondents (38.6 %) did not know when pharmacists actually substituted their medicines. About one in five (19.6 %) patients did not use their medicines after substitution because they were not sure of the brand supplied but 35.6 % have rejected substitution at one time and insisted on doctors' prescription. Respondents (14.9 %) agreed that brand substitution resulted in confusion while 24 % reported receiving brands that resulted in more side effects. More respondents (58.6 %) indicated that they never had a discussion with their pharmacists about the reasons for generic substitution and switches.

Conclusion: Generic substitution without adequate information resulted in confusion and subsequent lack of adherence. There is the vital need for appropriate policy and guidelines for generic substitution in Nigeria.