The dataset used covered under 65s in the US starting on antidepressant therapy between 2005 and 2007. Of 16,659 antidepressant users, 47.8% (n = 7,955) started on a brand-name medication and 52.2% (n = 8,704) started taking a generic product. During the follow-up 46.8% (n = 3,723) of brand-name users discontinued therapy compared to 44.2% (n = 3,843) generic users.

Almost half of those discontinuing therapy did not refill their initial prescription. For generic users 39.3%, 17.3% overall (n = 1,509) stopped therapy compared to 37.8%, 17.7% overall (n = 1,407) of brand-name users.

While 31.2%, 13.8% overall (n = 1,199) of generic users who discontinued the initial therapy switched to a different antidepressant compared to 32.9%, 15.4% overall (n = 1,224) of brand-name users.

The mean (median) time until discontinuation was 51.2 days (range 1 to 157 days) for generic users and 50.3 days (range 1 to 158 days) for brand-name users.

Most (68.0%) patients who discontinued from generic therapy did so in the first 60 days after starting treatment, and 84.4% discontinued therapy within the first 90 days. For brand-name users 69.9% of patients who discontinued did so in the first 60 days and 83.7% within the first 90 days after starting treatment.

Total healthcare costs in the first 180 days after starting treatment were lower for those using generics, averaging US$3,660 compared to US$4,587 for patients using brand-name drugs.

Disease-specific healthcare costs were also lower in patients who started therapy on a generic compared to a brand-name drug (US$803 vs US$1,125). While antidepressant drug costs for those starting on generics were found to be 43.7% lower for generic compared to brand-name drug users (US$174 vs US$309).

This research shows that patients starting generic antidepressants had lower drug costs and also lower overall healthcare costs compared to brand-name drug users [1], and that significant savings that can be made with the use of generic medicines as first-line agents in the treatment of major depressive disorder.

The results for discontinuation rates are so similar between generic and brand-name antidepressant drug users. The authors therefore concluded that patients who initiated therapy on a generic antidepressant were not more likely to discontinue therapy than patients who started a brand-name drug.

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No difference between generic and brand-name antidepressants

Reference

1. Vlahiotis A, Devine ST, Eichholz J, Kautzner A, et al. Discontinuation rates and health care costs in adult patients starting generic versus brand SSRI or SNRI antidepressants in commercial health plans. J Manag Care Pharm. 2011;17(2):123-32.