Pharmacoeconomic implications of preference toward reference- versus generic-brand antidepressants in primary care.

Background: The prevalence of depression is gradually increasing worldwide with an increasing utilization of antidepressants. Nevertheless, despite their lower costs, generic-brand antidepressants were reported to be less prescribed. We aimed to examine the costs of reference- versus generic-brand antidepressant prescriptions in primary care practice.

Methods: This cross-sectional study included electronic prescriptions for adult patients that contained antidepressants (World Health Organization's Anatomical Therapeutic Chemical (ATC) code: N06A), which were generated by a systematically selected sample of primary care doctors (n = 1431) in Istanbul in 2016. We examined the drug groups preferred, the reference- versus generic-brand status, and pharmacotherapy costs.

Findings: The majority of the prescriptions were prescribed for women (71.8%), and the average age of the patients was 53.6 ± 16.2 years. In prescriptions with a depression-related indication (n = 40 497), the mean number and cost of drugs were 1.5 ± 1.0 and 22.7 ± 26.4 United States Dollar ($) per prescription, respectively. In these prescriptions, the mean number and cost of antidepressants per encounter were 1.1 ± 0.2 and $17.0 ± 13.2, respectively. Reference-brand antidepressants were preferred in 58.2% of depression-related prescriptions, where the mean cost per prescription was $18.3 ± 12.4. The mean cost per prescription of the generics, which constituted 41.8% of the antidepressants in prescriptions, was $15.1 ± 11.4. We found that if the generic version with the lowest cost was prescribed instead of the reference-brand, the mean cost per prescription would be $12.9 ± 11.2.

Conclusions: Our study highlighted the substantial pharmacoeconomic impact of generic-brand antidepressant prescribing, whose preference over reference-brands could reduce the cost of antidepressant medication treatment by 17.5% in primary care, which could be approximately doubled if the cheapest generic antidepressant had been prescribed.