Download Penicillin allergy cross-‐reactivity • Roughly 10% of the population

Penicillin allergy cross-­‐reactivity • Roughly 10% of the population report a llergy to p enicillin • Penicillin is a b eta-­‐lactam antibiotic and can therefore cross-­‐react with other b eta-­‐lactam antibiotics • Beta-­‐Lactam Antibiotics o Penicillins  Amoxicillin  Amoxicillin/Clavulanic Acid ( Augmentin)  Ampicillin  Ampicillin/sulbactam (Unasyn)  Penicillin ( Pen G, Pen V K)  Piperacillin/Tazobactam ( Zosyn)  Nafcillin  Methicillin  Cloxacillin/Dicloxacillin  Ticarcillin/Clavulanate potassium (Timentin) o Cephalosporins  1st Generation • Cefazolin • Cephalexin ( oral) • Cefadroxil (oral) nd
 2 Generation • Cefuroxime • Cefoxitin • Cefotetan • Cefaclor/Loracarbef (oral) • Cefprozil (oral) • Cefuroxime axetil (oral) rd th
 3 /4 Generation • Cefepime ( 4th) • Ceftazidime (3rd) • Ceftriaxone (3rd) • Cefotaxime (3rd) • Ceftizoxime ( 3rd) • Ceftobiprole (3rd) • Ceftaroline (3rd) • Cefixime (oral – 3rd) • Ceftibutin (oral – 3rd) • Cefpodoxime/Cefdinir/Cefditoren (oral – 3rd)  Carbapenems 
• Meropenem ( Merrem) • Imipinem/cilastatin ( Primaxin) • Ertapenem (Invanz) • Doripenem (Doribax) Monobactam • Aztreonam Penicillin allergy • Among patients reporting an allergy to p enicillin, approximately 85-­‐90% will successfully tolerate a penicillin. o May n ever have had an allergy ( empirically listed PCN as an allergy) o Reactions such as GI upset, mild rash are not considered to b e a “true allergy” o Older patients who list an allergy to p enicillin may have experienced a reaction decades ago at a time where medication contamination was not uncommon (i.e., reacted to contaminant and n ot p enicillin itself) o May have b een taking a concurrent medication which precipitated a llergic reaction, but was falsely attributed to a p enicillin Cross-­‐Reactivity Rates • Cephalosporins o Cross-­‐reactivity rates between cephalosporins and p enicillin a llergy range from 0.17 to 8.4% • Carbapenems o Cross-­‐reactivity once thought to b e as h igh as 40% o Realistically, cross-­‐reactivity is approximately 1% • Monobactam ( Aztreonam) o There have b een n o reports of cross-­‐reactivity in patients with confirmed p enicillin allergy Recommendations for management in the Emergency Department • Determine if the patient is “truly” allergic to p enicillin, i.e., patient reports h istory of anaphylactic reaction o If yes, a void p enicillins, cephalosporins, and carbapenems o If no, p enicillins, cephalosporins, and/or carbapenems may b e administered with careful monitoring of airway •
To assist in d etermining the true nature of the a llergy, the following questions should b e answered b y the patient
o How o ld were you when the reaction o ccurred? o Can you d escribe the reaction? o When d id the reaction o ccur? After the f irst dose? After the tenth dose? o How was the p enicillin administered? Orally? Intravenously? o Were you taking any other medications a t the same time? o When the p enicillin was stopped, what happened? o Have you since taken a penicillin, cephalosporin, carbapenem, or monobactam?