Discussion

Apart from evaluating the trend of generic-brand antidepressant prescribing, our study is the first to reveal the pharmacoeconomic impact of this situation in primary care prescription data in Turkey. Revealing an overprescribing of reference brands, our findings suggest the preference of generics over reference antidepressants could reduce antidepressant-related costs in primary care by 17.5%. Moreover, this cost-saving could be doubled if the cheapest alternative available in the market had been selected, especially in terms of SSRIs, the most preferred antidepressant group in this study. Since most prescribed antidepressants are reference-brand drugs, our assumption is likely to underscore the considerable pharmacoeconomic impact of selecting generic-brand antidepressants over their reference-brand counterparts.

We previously reported the share of generic drug prescribing as 54.0% in Turkey between 2013 and 2016, with as low as 41.4% for depression prescriptions (Bayram et al., Reference Bayram, Aydin, Gelal, Aksoy and Akici2021). While this seemed to be consistent with our finding (41.8%), we observed it much lower for SSRIs (38.8%), the predominant group in depression pharmacotherapy. While mental health was reported to be one of four therapeutic areas accounting for the greatest savings afforded from generic drugs like antidepressants, various case reports and bioequivalence study results have led to debates that generic-brand antidepressants have disadvantages in efficacy and tolerability (Dunn et al., Reference Dunn, Cannon, Mitchell and Curtiss2006; Kautzner et al., Reference Kautzner, Vlahiotis, Devine and Eichholz2011; Association for Accessible Medicines, 2017). Furthermore, several case reports and studies describe clinical deterioration and reduced tolerability with generic substitution (Desmarais et al., Reference Desmarais, Beauclair and Margolese2011). In fact, many psychiatrists reportedly expressed concerns about generic drugs (Cessak et al., Reference Cessak, Rokita, Dąbrowska, Rozbicka, Zaremba, Mirowska-Guzel and Bałkowiec-Iskra2016). A survey conducted with psychiatrists in Germany reported that physicians preferred the reference-brand antidepressants for their own use more than the drugs they prescribe to their patients (Hamann et al., Reference Hamann, Mendel, Kissling and Leucht2013). It can be thought that these concerns may be among the reasons for the majority of reference-brand antidepressants in the treatment of depression in our study. On the other hand, a US study found no significant difference between those who started antidepressant treatment with the reference-brand and those who started with the generic-brand in terms of discontinuing the treatment (Dunn et al., Reference Dunn, Cannon, Mitchell and Curtiss2006). Therefore, considering its increasing frequency and share in terms of drug use, it can be considered one of the important intervention areas in increasing the use of generic-brand drugs in depression (Mojtabai and Olfson, Reference Mojtabai and Olfson2014).

Generic-brand drugs were reported to account for 89% of all prescriptions in 2016 in the USA, although accounting for just 27% of total prescription costs (Hamann et al., Reference Hamann, Mendel, Kissling and Leucht2013). One of the primary reasons for this is that the retail price of a generic drug is on average 75% less than that of a reference drug (Congressional Budget Office, 2010). Only with the use of generic-brand drugs instead of reference brands, health insurance expenditures in the USA were reported to decline by $67.6 billion and healthcare expenditures by $32.7 billion in 2015, emphasizing the slowdown of mounting US healthcare costs by switching to generic brands (Howard et al., Reference Howard, Harris, Frank, Kiptanui, Qian and Hansen2018). Consistent with this improvement, if the cheapest generic-brand antidepressant were chosen instead of the current reference-brand among our study population, the average antidepressant cost would decrease from $18.3 to $12.9 with an approximately 30% reduction, indicating that the use of generic-brand drugs in this drug group has an important place in health expenditures (OECD, 2019; Basara et al., Reference Basara, Caglar, Aygun and Ozdemir2019). In addition, considering that more than half of the antidepressant drugs are prescribed by primary care physicians in the country, this study contributed to uncover pharmacoeconomic reflections of the antidepressant prescribing patterns of primary care (Aydin et al., Reference Aydin, Cetin, Kurt, Savas, Acıkel, Kilic, Basoglu and Turkcapar2013).

In our study, approximately one-third of prescriptions containing antidepressants were generated for non-psychiatric diagnoses. A Canadian study examining primary care prescriptions between 2006 and 2015 reported that 55% of prescriptions containing antidepressants were diagnosed with depression (Wong et al., Reference Wong, Motulsky, Eguale, Buckeridge, Abrahamowicz and Tamblyn2016). In our study, we found that approximately half (49.3%) of the ACPs included a diagnosis of depression. This situation can be considered as a serious problem of irrationality in terms of rational pharmacotherapy principles. Therefore, drug-diagnostic mismatches in prescriptions can cause negative effects on cost-related processes such as reimbursement processes, as well as many medical problems. This might be further compelled by another finding in our study that we observed a higher frequency of generic-brand prescribing as the number of drugs per encounter increased, suggestive of concomitant chronic conditions. Contrarily, the use of generic-brand drugs in patients with chronic diseases was reported to be lower than in patients with less chronic diseases (Hassali et al., Reference Hassali, Kong and Stewart2005; Himmel et al., Reference Himmel, Simmenroth-Nayda, Niebling, Ledig, Jansen, Kochen, Gleiter and Hummers-Pradier2005). Therefore, it may be suggested that prescribing drugs for imprecise reasons with costly consequences could be regarded as another target for areas of development in raising awareness about the appropriate use of medicines.

Our study has some limitations. Receiving single-diagnosis prescriptions may lead to the elimination of various data; this allowed more specific and consistent inferences to be made in terms of diagnoses. On the other hand, the study provided primary care data, warranting additional evaluations of all health services. We used a comparably older data set, yet this is primarily because it was the most recent database we could access and since the coronavirus disease 2019 (COVID-19) pandemic has altered the prescribing routines of physicians, etc. We preferred to use the data set of a large metropolitan city that we could access in the pre-COVID-19 period so that differences such as these have little impact on our findings.

In conclusion, our study showed higher prescribing rates of reference-brand antidepressant drugs in depression pharmacotherapy in primary practice. Physicians who chose generics over reference-brand antidepressants in primary care could downshift the cost of antidepressant medication treatment by 17.5%, with a potential doubling of this cost-saving if the cheapest generic-brand antidepressant drugs had been preferred. This indicates the need for reemphasizing generic-brand drug awareness in depression pharmacotherapy with respect to cost-effective health expenditure measures. Moreover, the reproducibility of our study in other countries and the comparative assessment could further emphasize the global importance of adopting cost-effective health expenditure measures in depression pharmacotherapy in primary practice.