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5/12/2014

Iowa Pharmacists Fill Allergy Testing Niche

Kate Traynor

For more than a decade, a pharmacist-run service at an Iowa hospital that tests patients for penicillin sensitivity has faced ups and downs, but the hospital has ultimately remained committed to the program.

The service, at Iowa Methodist Medical Center, a 670-bed community-based teaching hospital in Des Moines, was described in the June 15, 2004, issue of AJHP.

"We were looking for ways to, basically, improve the ability to use antimicrobials," recalled Geoffrey C. Wall, internal medicine clinical pharmacist and lead author of the report. "As with most hospitals, I think, we realized that we were using a whole lot of alternative medications for patients with supposed penicillin allergies."

According to the report, pharmacists evaluated 26 patients for penicillin allergy, and skin test results were negative in all but one of the 23 patients who met the criteria for testing. The test result was indeterminate for the remaining patient, and all 26 were subsequently treated with penicillin without incident.

Wall said the idea for the allergy testing service was inspired by two events—his periodic occupational tuberculin skin test and a report published in 2000 in the journal ChestExternal Link that described a penicillin allergy test pilot program administered by allergy fellows.

"We don't require a pulmonologist to read a [tuberculin test], so why do you have to be an allergist to do penicillin skin tests?" Wall recalled of his thinking at the time.

Iowa state law allows pharmacists to engage in collaborative practice agreements with physicians, and the state doesn't restrict the arrangements to specific settings or diseases.

Wall said this allows Iowa pharmacists to work "outside what I think would normally be considered the scope of practice, as long as there's a protocol that is overseen by physicians" and approved by the hospital.

He said the physician head of allergy at Iowa Methodist "used to be a pharmacist" and initially taught staff pharmacists how to perform and interpret the skin tests. The service was made available to infectious diseases (ID) physicians, who raved about it and even promoted the pharmacists' work at national meetings.

Despite its positive start, the service soon became a victim of unforeseen events.

The testing protocol required the use of Pre-Pen, the only product on the U.S. market for performing skin tests for penicillin sensitization. But manufacturing woes led to diminished availability of the product starting around 2001, followed by the withdrawal of Pre-Pen in 2004.

"In the world of allergy it was a really big deal, because you couldn't do penicillin allergy skin tests anymore," Wall said. "So we had to put the service on hold."

A different manufacturer received FDA approval to market Pre-Pen in late 2009, allowing the hospital to restart the pharmacy-managed service around 2010.

Wall estimated that the service has conducted 30–40 skin tests since then, and just one patient has had a positive test result.

"We'd love to go gangbusters on it, but we simply don't have the pharmacy staff to pull it off," Wall said. He said that over the years, he has twice been "the last person standing who was still working and knew how to do the testing."

The pharmacy staff is currently regrouping with the support of a clinical coordinator who is very supportive of the program.

"We've really taken baby steps this time around, simply because it is somewhat time-consuming. It really will take about 45 minutes to an hour of a pharmacist's time to do it, at least in the configuration that we have set up," Wall said in April. "My hope is that over the course of the next six months we'll have a cadre of pharmacists trained, so it's not all on one pharmacist's shoulders."

Wall said that the skin test, if warranted on the basis of the pharmacist's assessment of the patient, is performed in accordance with the manufacturer's instructions and guidance from the American Academy of Allergy, Asthma & Immunology. The results are then communicated to the ID physician.

"If they are going to go to a penicillin, we usually do a graded challenge on them, just for an extra level of safety," Wall said. The graded challenge consists of gradually increasing the dose of penicillin, administered orally, to largely rule out the risk that the patient will suffer a serious allergic reaction during therapy.

According to the Centers for Disease Control and Prevention, just 10% of patients who report a severe allergy to penicillin remain allergic throughout their lives. When properly performed, skin testing identifies up to 97% of patients who are allergic to penicillins.

"You can feel pretty comfortable that if the test's negative . . . you can give this patient a penicillin with the same fears that you would give it to somebody that doesn't say that they're allergic," Wall said. "That's what we actually say in our notes—that the patient should be able to tolerate penicillin as well as the general population that does not claim a penicillin allergy."

He said that patients who say they are allergic to penicillin are often unable to describe their past response to the drug. They often tell the pharmacist that their parents told them decades ago that they were allergic and should never take the drug. And even patients who can describe an allergic response they had during adulthood have tested negative and been successfully treated with a penicillin.

Wall said the service provided at his hospital is more than a simple penicillin skin test program.

"We really like to call it an allergy assessment or a drug allergy assessment program," he said. "We actually do a lot of talking with the patients to see how much we can find out about [their] drug allergies."

A report in the March 2014 Journal of Allergy and Clinical ImmunologyExternal Link found an association between reported penicillin allergy and increased hospital use as well as a significant increase in the use of fluoroquinolones, clindamycin, and vancomycin. The patients who were labeled penicillin-allergic also had higher rates of serious infection, including infections associated with antimicrobial use, than patients who did not report a penicillin allergy.

Wall said he is unsurprised by the findings of that study.

"When you're using alternative drugs to β-lactams, you often do have to select drugs that are more expensive, or drugs that have more adverse effects, or drugs that may not be the drugs of choice," he said.

He believes the program at Iowa Methodist benefits the hospital and its patients by supporting the wider use of penicillins and limiting the use of alternative antimicrobials.

Wall has helped to trained pharmacists at other area hospitals how to perform skin tests, but he doesn't know if any of these institutions went on to implement a program like the one at his hospital. In some cases, he said, a state's pharmacy practice act may prevent pharmacists from administering the tests.

But if state law doesn't stand in the way, and good institutional support and training are available, pharmacists may be able to replicate the Iowa Methodist program at their own hospitals.

"I think it's worth it," Wall said. "I think this is an area that's definitely in pharmacy's wheelhouse."

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