Patricia J. Markus

Safety and effectiveness of a preoperative allergy clinic in decreasing vancomycin use in patients with a history of penicillin allergy

BACKGROUND We developed a clinical pathway to optimize the use of antimicrobials by decreasing vancomycin use in preoperative patients with a history of penicillin allergy. OBJECTIVE To decrease the use of vancomycin in surgical patients with a self-reported penicillin allergy. METHODS In June 2002, same-day allergy consultation and penicillin skin testing were made available for preoperative patients with self-reported penicillin allergy at the preoperative evaluation (POE) clinic. We reviewed the penicillin allergy skin test results, recommendations, and beta-lactam antibiotic administration outcomes from July 1, 2002, to September 16, 2003. RESULTS A total of 1,204 of 11,819 patients were evaluated for beta-lactam allergy at the POE clinic. Of these, 1,120 were approved by the institutional review board for inclusion in the study and 9 were excluded from the study. Of the remaining 1,111 patients, 1,030 (93%) underwent skin testing for penicillin allergy. Forty-three (4%) had a positive skin test result to penicillin. A total of 947 (85%) of the 1,111 patients with a history of beta-lactam allergy were advised to use a beta-lactam antibiotic, and 164 (15%) were advised to avoid beta-lactams. A total of 955 patients (86%) actually received preoperative antibiotics. Of these 955 patients, 716 (75%) received cefazolin, and only 149 (16%) received vancomycin compared with 30% historical controls (P < .01). Among the patients with a negative penicillin skin test result who received a cephalosporin, 5 (0.7%) of 675 experienced an adverse drug reaction to a cephalosporin. CONCLUSIONS Establishment of a clinical pathway in a preoperative clinic that includes allergy consultation and penicillin skin testing reduced vancomycin use to only 16% in surgical patients with a history of beta-lactam allergy.

Reduction of Vancomycin Use in Orthopedic Patients With a History of Antibiotic Allergy

Objective To reduce prophylactic vancomycin use in patients with a history of penicillin or cephalosporin allergy undergoing elective orthopedic surgery by using a targeted allergy consultation and penicillin allergy skin testing. Patients and Methods The participants in this practice improvement study were patients with a history of penicillin or cephalosporin allergy who were scheduled for elective orthopedic surgery and referred by orthopedic surgeons for allergy consultation and penicillin allergy skin testing between September 22, 1998, and April 15, 1999. The primary outcome measure was the percentage of participants who received prophylactic cefazolin during the study period compared with historical controls. Results Of the 60 study patients, 59 received a penicillin allergy skin test, 58 underwent orthopedic surgery, and 55 received antibiotic prophylaxis. Fifty-five patients had a history of allergy to penicillin, a cephalosporin, or both, and 5 had a history of nonspecific antibiotic allergy. Of the 59 patients, 55 (93%) had negative penicillin allergy skin test results. Fifty-four (90%) of the 60 patients were given clearance by the allergist to receive cefazolin. Of the 55 study patients who received antibiotic prophylaxis, 6 (11%) received vancomycin compared with 38 (30%) of 127 historical controls ( P ≤05). None of the study patients had an immediate reaction to cefazolin or to vancomycin. Conclusion Prophylactic vancomycin use in patients with a history of penicillin or cephalosporin allergy undergoing elective orthopedic surgery can be reduced by a targeted allergy consultation and penicillin allergy skin testing.

Female sex as a risk factor for penicillin allergy

BACKGROUND Identification of risk factors is an integral part of a physicians evaluation of a patient. OBJECTIVE To determine whether female sex is an independent risk factor for penicillin allergy. METHODS Rates of positive penicillin skin test (PST) results, according to sex, were determined in patients with a history of penicillin allergy undergoing penicillin allergy evaluation with major and minor determinants of penicillin between June 1, 2002, and June 30, 2004. Univariate and multivariate logistic regression analyses were used to calculate unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for sex differences in the rates of positive PST results. RESULTS Of the 1,921 patients, 1,759 underwent PST and 157 did not; 5 medical records were not available for review. The mean patient age was 60 years. Sixty-four patients (4%) had a positive PST reaction; of these, 53 (83%) were females and 11 (17%) were males (OR, 3.6; 95% CI, 1.9-7.2; P < .001). In a multivariate logistic regression analysis adjusted for age, history of multiple drug allergies, and elapsed time from the initial penicillin adverse drug reaction to PST, female sex again had a significant risk of a positive PST reaction (OR, 3.2; 95% CI, 1.6-6.7; P = .001). CONCLUSION A greater risk of penicillin allergy exists in association with female sex in patients with a history of penicillin allergy.

Preoperative evaluation of patients with history of allergy to penicillin: Comparison of 2 models of practice

OBJECTIVE To study whether allergy consultation and penicillin allergy skin testing affects the selection of antibacterial prophylaxis perioperatively in surgical patients with history of allergy to penicillin (HOAP). PATIENTS AND METHODS From January 1 through June 30, 2004, we compared 2 different models of practice at our institution. At the Preoperative Evaluation Clinic (POEC), all patients with HOAP are evaluated by an allergist and undergo skin testing for allergy to penicillin. At other (non-POEC) preoperative evaluation settings (OPES), patients with HOAP do not undergo allergy consultation and penicillin skin testing before surgery. Of the 4889 patients screened at the POEC during the study period, 412 consecutive patients with HOAP were included in the study. Of the 416 patients screened at OPES, 69 consecutive patients with HOAP were studied. Logistic regression was used to assess whether allergy consultation was associated with the choice of antibiotic for antibacterial prophylaxis perioperatively, after adjusting for age, sex, and type of surgery. RESULTS Perioperative cephalosporin use was greater among patients screened at POEC vs those screened at OPES (70% vs 39%, P<.001 unadjusted; P=.04 adjusted for age, sex, and type of surgery). Vancomycin use was lower for patients screened at POEC vs those screened at OPES (10% vs 28%, P<.001 unadjusted; P=.03 adjusted). CONCLUSION For patients with HOAP, evaluation at the POEC was associated with increased use of cephalosporin and decreased use of vancomycin.

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.

999 Reduction of vancomycin use in orthopedic patients with a history of antibiotic allergy

OBJECTIVE To reduce prophylactic vancomycin use in patients with a history of penicillin or cephalosporin allergy undergoing elective orthopedic surgery by using a targeted allergy consultation and penicillin allergy skin testing. PATIENTS AND METHODS The participants in this practice improvement study were patients with a history of penicillin or cephalosporin allergy who were scheduled for elective orthopedic surgery and referred by orthopedic surgeons for allergy consultation and penicillin allergy skin testing between September 22, 1998, and April 15, 1999. The primary outcome measure was the percentage of participants who received prophylactic cefazolin during the study period compared with historical controls. RESULTS Of the 60 study patients, 59 received a penicillin allergy skin test, 58 underwent orthopedic surgery, and 55 received antibiotic prophylaxis. Fifty-five patients had a history of allergy to penicillin, a cephalosporin, or both, and 5 had a history of nonspecific antibiotic allergy. Of the 59 patients, 55 (93%) had negative penicillin allergy skin test results. Fifty-four (90%) of the 60 patients were given clearance by the allergist to receive cefazolin. Of the 55 study patients who received antibiotic prophylaxis, 6 (11%) received vancomycin compared with 38 (30%) of 127 historical controls (P < or = .05). None of the study patients had an immediate reaction to cefazolin or to vancomycin. CONCLUSION Prophylactic vancomycin use in patients with a history of penicillin or cephalosporin allergy undergoing elective orthopedic surgery can be reduced by a targeted allergy consultation and penicillin allergy skin testing.