Wednesday, July 28, 2021

Piperacillin-tazobactam and penicillin allergy

PulmCrit (EMCrit)
PulmCrit - July 28, 2021 - By Josh Farkas
  • Allergy to beta-lactam antibiotics is mediated by the R side chain, rather than the core structure. Thus, patients are not allergic to all beta-lactams, nor all penicillins. Rather, patients tend to be allergic to a select group of antibiotics with similar R side-chain structure.
  • The side-chain structures of piperacillin and nafcillin are quite dissimilar from other penicillins, so they wouldn’t be expected to be cross-allergic with other penicillins.
  • Recent studies show that most patients who are allergic to piperacillin-tazobactam do not demonstrate allergic cross-reaction with either natural penicillins or amoxicillin. 
  • Occasional patients do have allergy to both piperacillin-tazobactam and to penicillin. This may reflect that some patients have a hyperallergic phenotype, with the development of numerous unrelated drug allergies.
  • The label of “penicillin allergy” is not an absolute contraindication to using piperacillin-tazobactam or nafcillin. Patients should be carefully considered on an individual basis.