Fran Lowry

November 14, 2012

ANAHEIM, California — Patients who have had an adverse drug reaction in the past, or who have a history of atopy, including asthma, eczema, or allergic rhinitis, might be at increased risk for more severe adverse drug reactions, according to a study presented here at the American College of Allergy, Asthma & Immunology 2012 Annual Scientific Meeting.

As a result of this finding, physicians should be more vigilant with these patients when they prescribe a new medication, lead author Janelle M. Sher, MD, from Winthrop Hospital, Mineola in New York, told Medscape Medical News.

Dr. Janelle Sher

"Adverse drug reactions occur commonly, but there aren't a lot of studies that actually look at the severity of these reactions, specifically those that are allergic and immunologic in origin and cause hives, urticaria, angioedema, and cutaneous first drug reactions," Dr. Sher said.

To assess the risk factors associated with the severity of an adverse drug reaction in their hospital, Dr. Sher and her team conducted a retrospective chart review of 369 adverse drug reactions that occurred over a 13-month period (May 1, 2011 to May 31, 2012).

The reactions were categorized as mild (no treatment given), significant (treatment needed, no residual effects), serious (longer hospital stay but no permanent disability), major (permanent disability or life threatening), and fatal.

There were 51 mild (13.8%), 140 serious (37.9%), 148 significant (40.1%), and 2 major (0.5%) adverse drug reactions.

In addition, the researchers found that adverse drug reactions occurred more often prior to admission (61.8%), and these were more severe than those that occurred during admission (odds ratio [OR], 1.47; 94% confidence interval [CI], 0.96 - 2.24).

Sixty adverse drug reactions were atopic in origin, and the most common drugs causing the reaction were intravenous contrast (in 21.0% of the cases) and fluoroquinolone antibiotics (in 12.0%).

The majority of the people who experienced an allergic or immunologic adverse drug reaction were women (53.3%); their mean age was 55.3 years.

Patients with a history of atopy were almost 5 times more likely to have a severe adverse drug reaction (OR, 4.74; 95% CI, 0.54 - 41.4).

Patients with a previous adverse drug reaction were 16% more likely to have a severe adverse drug reaction (OR, 1.16; 95% CI, 0.4 - 3.3).

"All doctors, whether you are an allergist, immunologist, or in the primary care field, should be investigating whether your patient has had a previous adverse drug reaction or if they have a history of atopy as defined in this study," Dr. Sher said.

"They should institute closer follow-up of these patients if they are prescribing a new medication. Bring them back sooner and ask, even if just with a telephone call, if they have experienced symptoms such as hives, urticaria, angioedema, or rash," she said.

"If we could identify an at-risk population, the hope is that we would reduce the risk of such serious events, said John Oppenheimer, MD, clinical professor of medicine at New Jersey Medical School in Newark, who was not part of the study.

Known risk factors for severe adverse drug reactions include being female, previous drug allergy, and multiple exposures. However, in previous studies, atopy "has not been a risk factor," he said.

"This study is of interest and indicates a need for large-scale studies to resolve whether atopy is truly a risk factor for more severe adverse drug reactions," he explained.

Jay M. Portnoy, MD, professor of pediatrics at the University of Missouri and Mercy Children's Hospital, both in Kansas City, agrees that all physicians should be aware of their patients' adverse drug reaction history.

"This is a reminder to all doctors to ask about previous drug reactions and to recommend that their patients be evaluated by an allergist," he told Medscape Medical News. "By the time the drug is needed in the hospital, it may be too late to do an effective evaluation," Dr. Portnoy said.

He added that patients should ask about all drugs being given in the hospital and remind healthcare providers about their history.

Dr. Sher has disclosed no relevant financial relationships. Dr. Oppenheimer reports financial relationships with GlaxoSmithKline, Merck, AstraZeneca, Boehringer Ingelheim, MedImmune, and Novartis. Dr. Portnoy reports financial relationships with ThermoFisher Scientific.

American College of Allergy, Asthma & Immunology (ACAAI) 2012 Annual Scientific Meeting: Abstract P22. Presented November 11, 2012.