Women, on the other hand, report nausea most frequently, and make more reports in general.

The FDA collects data on every adverse reaction to prescription drugs reported by pharmaceutical companies, doctors, and the general public. This analysis is based on a new FDA initiative called OpenFDA that’s supposed to make that publicly available data more accessible online.

But the results should not be taken to imply that death is a common side effect. There are a few very important notes of caution about interpreting the data, part of a project that the FDA warns is in beta and “not for clinical use.”

Some Caveats

In this data release, the FDA includes the more than 3.6 million reports the agency received between 2004 and 2013. But not every reaction is necessarily reported to the FDA, and not every report is necessarily accurate. Consider that “death” is much more likely to be reported than more mundane adverse reactions, and that people may attribute any given effect to a drug they have recently taken, even if the events are entirely unrelated.

Because of the sheer number of reports received, they’re not evaluated on an individual basis — the FDA moves to act when a growing number of reaction reports indicate there may be a problem with a particular drug. Crucially, that means these must be interpreted as a tally of reported drug reactions, not actual drug reactions, which would be impossible to measure without more thorough data collection and validation.

According to the site, most reports come from manufacturers. But the ones that come from the general public can be submitted by anyone online, and some are mailed in.

What We Can Learn

Even though the accuracy and comprehensiveness of the reports are unknown, there’s some fascinating information available. Here are a few major points:

• The number of reported bad reactions trends upwards over time. In January of 2004, there were 13,310 adverse reactions reported. In June of 2013, the most recent month available, there were 43,259 — which has dropped from a high of 80,787 in January of 2013. The last time the number dipped below 40,000 was February of 2011. The FDA attributes the rise to improved reporting.
• There are more serious reactions reported for nonsteroidal anti-inflammatory drugs like ibuprofen or asprin than for any other drugs, including antipsychotics and benzodiazepines (like Valium). It’s likely that this indicates how widely used ibuprofen and aspirin are, not that they are more dangerous than other drugs.
• It’s hard to say whether drugs are being used as recommended, or if important data is going unreported. In the lists of reasons that the person in a report took a drug, the top two reasons were different categories of “unknown.”
• There are not many more deaths reported in men than in women — women are just even likelier to report other side effects. There just over 60,000 deaths reported for women and 63,225 for men. But women reported eight other factors more frequently than men. This could mean that men experience fewer other side effects, but it could also mean that adverse side effects that affect men are less likely to be reported.
• There are many more reports for women than there are for men — 2 million versus just under 1.3 million — and women were more likely to report more than one effect and to do so themselves. Most reports for men came from their doctors or from pharmaceutical companies.

Right now, the system can search adverse drug reaction reports going back to 2004. The FDA plans to make its databases of food and medical device reports available for searching soon.