The Friday Effect: Firm Lobbying, the Timing of Drug Safety Alerts, and Drug Side Effects

Abstract

Safety alerts are announcements made by health regulators warning patients and doctors about new drug-related side effects. However, not all safety alerts are equally effective. We provide evidence that the day of the week on which the safety alerts are announced explains differences in safety alert impact. Specifically, we show that safety alerts announced on Fridays are less broadly diffused: they are shared 34% less on social media, mentioned in 23% to 66% fewer news articles, and are 12% to 51% less likely to receive any news coverage at all. As a consequence of this, we propose Friday alerts are less effective in reducing drug-related side effects. We find that moving a Friday alert to any other weekday would reduce all drug-related side effects by 9% to 12%, serious drug-related complications by 6% to 15%, and drug-related deaths by 22% to 36%. This problem is particularly important because Friday was the most frequent weekday for safety alert announcements from 1999 to 2016. We show that this greater prevalence of Friday alerts might not be random: firms that lobbied the U.S. Food and Drug Administration in the past are 49% to 56% more likely to have safety alerts announced on Fridays. This paper was accepted by Stefan Scholtes, healthcare management.