According to the Indiana University School of Medicine, which looked at and analyzed 5,600 labels, the more commonly prescribed drugs can have up to 100 listed side effects, and the highest number researchers saw was 525 reactions. The long list is likely due to manufacturers trying to avoid potential lawsuits.
"But having all these labeled side effects can overwhelm doctors who must weigh the risks and benefits when prescribing a medication," lead author of the study Dr. Jon Duke said. "The Food and Drug Administration has taken steps to discourage such 'overwarning,' but at present information overload is the rule rather than the exception."
Those drugs with the greatest number of side effects were antidepressants, antiviral medications and new treatments for restless legs syndrome and Parkinson's disease. Those drugs used by neurologists and psychiatrists tend to have the most complex labels, compared to those used by neurologists, opthamologists and dermatologists, which generally have the fewest.