O03 Penicillin and cephalosporin cross-reactivity: a single-centre UK study

Abstract Background Penicillin allergy (PenA) labels limit antimicrobial options, and concerns about cross-reactivity between penicillin cephalosporins can further restrict prescribing. Alternative therapies are associated with reduced efficacy, poorer safety profiles increased healthcare costs. Emerging literature suggests the incidence of penicillins may be lower than historically reported rates 2–10%. Furthermore, there is a lack real-time data evaluating percentage patients PenA who tolerate cephalosporin. Objectives To determine label tolerated in secondary care setting. Methods Patients prescribed cephalosporin from 01 January 2016 to 31 December 2020 at Leeds Teaching Hospitals NHS Trust (LTHT) were identified using inpatient electronic prescribing system. 1613 extracted for analysis. The team reviewed clarified whether each patient (i) had that was potential hypersensitivity reaction, intolerance, or unknown/undocumented (ii) Tolerance defined as receiving ≥1 dose without adverse effects subsequent label. We recorded if intolerance documented reason stopping Results There 1279 received 555 (43%) documentation in-keeping IgE-mediated allergic reaction penicillins, 177 (14%) deemed have an 547 unknown undocumented 1263 (98.7%) Six (0.5%) stopped due intolerance. One asked stop therapy ‘changes’ skin. Nine (0.7%) developed possible symptoms cephalosporin; 4 rash, 2 facial lip swelling (without airway compromise), 1 hypotension, difficulty breathing chest pain, breathlessness itching. Of 9 reactions; 5 classified reactions. Four reactions penicillins. Eight 2nd-generation (cefuroxime) 3rd generation (cefotaxime). Conclusions rate following administration any LTHT 0.7%. estimated 1–3% general population (with/without label). conclude that, history unverified, non-anaphylactic label, could administered risk reaction.