Penicillin is the most frequently reported cause of drug allergy, and cross-reactivity of penicillins with other beta-lactam antibiotics is an area of debate. This review evaluates the available data on immunoglobulin E-mediated penicillin hypersensitivity and cross-reactivity with cephalosporin, carbapenem, and monobactam antibiotics. A MEDLINE search was conducted from 1950 to October 2013, and selected references from review articles were also evaluated. There is a wide variety in reported incidences of cross-reactivity between penicillins and cephalosporins or carbapenems, with early retrospective studies suggesting up to 41.7% and 47.4% cross-reactivity, respectively. Conversely, the use of monobactam antibiotics is frequently employed in the case of a penicillin allergy, as prescribers believe that there is no cross-reactivity between the 2 drug classes. More recent prospective studies suggest that the rates of cross-reactivity with cephalosporins and carbapenems are <5% and <1%, respectively. Similarities in penicillin and cephalosporin side chains may play a role in cross-reactivity between these classes. Cross-reactivity with monobactams is essentially negligible; however, there are some clinical data to support an interaction between ceftazidime and aztreonam, due to the similarity of their side chains. The data reviewed suggest that avoidance of other beta-lactams in patients with type 1 hypersensitivity to penicillins should be reconsidered.

Background Tocilizumab (TCZ) was approved by the Food and Drug Administration under emergency use authorization for treatment of COVID-19 in patients requiring supplemental oxygen, non-invasive or invasive mechanical ventilation, or extracorporeal membrane oxygenation. Despite multiple clinical trials, there remain unanswered questions surrounding TCZ use. Methods This multi-hospital retrospective cohort study included patients who received TCZ for COVID-19 between January 29th, 2021 and June 30th, 2021 at five University of Pennsylvania Health System (UPHS) hospitals. Patients were eligible for TCZ per UPHS criteria if they scored ≥ 5 on the World Health Organization (WHO) ordinal scale for ≤ 24 hours and experienced &lt; 14 days of acute COVID-19 symptoms. Descriptive statistics were performed to characterize usage within the health system. Results This study evaluated 134 patients who received TCZ for the treatment of COVID-19. TCZ was ordered a median of 22 hours (interquartile range [IQR], 13.2 – 41.5) after hospital admission. A majority of patients (76.1%) were admitted to the intensive care unit and a small portion (12.7%) had a WHO ordinal scale that was &gt;5 at time of TCZ order entry. All patients received concomitant dexamethasone therapy at a total prednisone equivalent of 400 mg (IQR, 335.6 – 480). Overall 33.6% of patients experienced an adverse event (ADE) within 30 days of TCZ administration (Table 1). Most common ADEs included bacterial infection (29.9%), hepatitis (6.7%), and fungal infection (3%); other etiologies of ADEs were not accounted for. All-cause mortality (Table 2) at day 30 occurred in 20.9% of patients and median time from TCZ administration to mortality was 12.5 days (IQR 5 – 18.3). Ninety-six patients in the cohort (71.6%) were discharged by day 30. Of the subgroup discharged by day 30, the majority (70.8%) were discharged to home. Conclusion Patients who received TCZ for severe COVID-19 experienced 20.9% mortality; mortality was higher among those with higher ordinal scale at the time of TCZ dosing. A large portion of patients (70.8%) were discharged to home within 30 days. One third of patients experienced an adverse event, primarily bacterial or fungal infection. Our experience may be useful in counseling patients about anticipated effects of TCZ. Disclosures George L Anesi, MD, MSCE, AHRQ, NHLBI, UpToDate: Advisor/Consultant|AHRQ, NHLBI, UpToDate: Grant/Research Support Kathleen Degnan, MD, Gilead: Grant/Research Support.

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