Philadelphia – Drug safety warnings issued by the US Food and Drug Administration (FDA) don't always lead to targeted changes in the way medications are prescribed and used, reports a study in the June issue of Medical Care. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.

"While some FDA drug risk communications had immediate, strong impact, many had either delayed or no impact on health care utilization or health behaviors," concludes the new report. The study was led by Stacie B. Dusetzina, PhD, of Harvard Medical School and Ashley S. Higashi, MPD, of University of Chicago Hospitals.

Some FDA drug risk advisories had 'unintended consequences'

The researchers analyzed 49 studies—published between 1990 and 2010—evaluating the impact of FDA drug risk communications. After identifying a new safety concern, the FDA uses various ways to communicate the risks and recommended precautions, such as "Safety Alerts" issued to the general public or "Dear Healthcare Provider" letters sent to prescribers. For particularly severe risks, the FDA may modify the drug warning label to include a "Black Box" warning.

The 49 studies covered 16 different medications or types of drugs. Most of the studies were based on medical records or prescription claims.

The results suggested that different types of FDA warnings had differing effects. Advisories calling for increased monitoring generally led to decreased use of the drug, but only small and temporary increases in monitoring. Recommendations against co-prescribing drugs with potentially dangerous interactions often took months or years to show an effect. Warnings targeting specific groups of patients sometimes "spilled over" into other groups.

Repeated FDA warnings showed larger but delayed effects, but were more likely to affect new prescriptions than patients already using the drug. Warnings about specific drugs had larger effects; the effects on drug substitution varied depending on the clinical situation.

Mixed effects of warnings on antidepressants in children

Many of the studies evaluated the impact of FDA warnings about a possible increase in suicide risk among children and adolescents taking antidepressant drugs. Most studies showed decreased prescribing of antidepressants to children, along with smaller increases in antidepressant prescribing for adults.

The studies reported shifts in market share to different antidepressants, with mixed evidence on the use of psychotherapy as an alternative to antidepressants. There was little information on how the warnings affected health outcomes for children and teens with symptoms of depression. However, one study suggested an increase in suicides among youths related to declines in antidepressant prescribing.

"Risk communication is a complex science and understanding the intended and unintended outcomes from prior FDA advisories, and label warnings may help to guide future risk communication," write Dusetzina, Higashi, and colleagues. They note that the published studies of the effects of FDA safety warnings had significant limitations. There was little or no data on how drug warnings affect patient-doctor communication, decision-making, or perceived risks.

However, the studies are not the first to show unintended consequences of regulatory warnings regarding prescription drugs. "[This] potential demonstrates the challenge that policy-makers face to design risk messages that are maximally effective, specific, and that don’t become risks themselves," the researchers conclude. They call for further studies to look at how FDA advisories affect prescribing and medical practice, and to "enhance the science of risk communication regarding prescription drugs."

In an accompanying editorial, Dr Gerald J. Dal Pan of the FDA's Center for Drug Evaluation and Research discusses the complex challenges involved in communicating the risks of medicines and evaluating the impact of those communications. He notes the introduction of a new type of "Drug Safety Communication" as the FDA's "primary safety communication tool for postmarket issues," with the potential to provide prescribers with a more detailed understanding of emerging issues.

This article was first published at www.newswise.com

Please LIKE our Facebook page - it makes us stronger