Collaboration between allergists and pharmacists increases β-lactam antibiotic prescriptions in patients with a history of penicillin allergy.

Background: Over 90% of patients with a history of penicillin allergy have negative penicillin skin tests. Pharmacists are trained to identify and resolve medication-related problems. We hypothesized that collaboration between allergists and pharmacists to identify and evaluate patients with a history of penicillin allergy would increase β-lactam antibiotic prescription.

Methods: We conducted a prospective observational study in which patients with a history of penicillin allergy were identified and educated at the pharmacy about penicillin allergy and offered an allergist consultation with a penicillin skin test. All patients were followed up to determine which antibiotics were subsequently prescribed.

Results: A total of 503 patients were enrolled, and 71 (14%) were evaluated by an allergist. Sixty-seven of these 71 patients (94%) had a negative penicillin skin test. Twenty-nine patients evaluated by an allergist and 205 patients not evaluated were prescribed antibiotics. Patients prescribed antibiotics and evaluated by an allergist were compared to those not evaluated by an allergist, with the following results: 19 of 29 patients (66%) were prescribed a β-lactam antibiotic compared to 54 of 205 (26%; p < 0.0001); 8 of 29 patients (28%) were prescribed penicillin compared to 7 of 205 (3%; p < 0.0001); 15 of 29 patients (52%) were prescribed a cephalosporin compared to 48 of 205 (23%; p < 0.01), and 10 of 29 patients (34%) were prescribed a non-β-lactam antibiotic compared with 177 of 205 (86%; p < 0.0001).

Conclusion: A collaborative effort between allergists and pharmacists can increase β-lactam antibiotic prescriptions and decrease non-β-lactam prescriptions in patients with a history of penicillin allergy.