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