According to a study, companies didn't report approximately one in 10 severe and unexpected medication side effects to the US Food and Drug Administration (FDA). The reports were to be given within a 15-day time that was specified by federal regulations in order to protect patient safety.

Researchers at the University of Minnesota carried out the study. According to an analysis of 1.6 million side effects reported to the FDA from 2004 to 2014, drug manufacturers generally do not disclose serious adverse events within this period when patient deaths occur.

According to senior study author Pinar Karaca-Mandic, a researcher at the University of Minnesota School of Public Health in Minneapolis, "Timely reporting of adverse drug events is critical for ensuring patient safety. Ours is the first study to empirically examine the extent of delays in reporting".

As per US regulations, when pharmaceutical companies realize serious complications associated with patient hospitalizations, disabilities, deaths, birth defects or earlier unknown side effects, they need to reveal these problems to the FDA as soon as they become aware. They should prefer to tell this over minor problems or complications that are already explained on medication labels.

It was analyzed by Karaca-Mandic and colleagues that since how long companies were told regarding serious side effects until problems were reported to the FDA. On the whole, companies didn't disclose 160,383 severe adverse events, or 10% of reports within 15 days, together with approximately 40,500 reports that involved patient deaths.