In their recent study report in the In Practice section of the Journal of Allergy and Clinical Immunology, Dorman et al acknowledged that patients with a history of penicillin allergy who are found to be skin test negative to penicillin are able to tolerate repeated oral doses of penicillin with low rates of resensitization. However, the resensitization rate after repeated doses of intravenous penicillin, they added, was less clear.

They therefore sought to evaluate the risk of allergic reactions to repeated doses of intravenous penicillin in patients who previously reported penicillin allergy and were found to be penicillin skin test and oral challenge negative.

A retrospective review was conducted between 2010 and 2016 of adult patients who were treated at academically affiliated hospitals. Patients included in the review had negative penicillin allergy testing and were treated with 2 or more courses of intravenous penicillins. Charts were evaluated to identify any adverse drug reactions.

Discussing their results, the researchers explained that the index penicillin-associated reactions ranged from rash to hypotension and were, for the most part, remote as 75% had reported reactions more than 10 years previously. More than 50% of patients received 3 or more courses of intravenous penicillins. The most frequently repeated intravenous penicillin overall was piperacillin/tazobactam. Thirty-two patients received a total of 111 courses of intravenous penicillins and none developed an immediate hypersensitivity reaction.

Concluding that repeated administration of intravenous penicillin antibiotics appear to be safe In patients who report penicillin allergy and have negative penicillin allergy testing, the authors suggest nonetheless that larger prospective studies should be performed to confirm these observations.

SOURCE/REFERENCE: Dorman et al: Risk of Allergic Reactions to Recurrent Intravenous Penicillin Administration in Penicillin Skin Test Negative Patients;