Anaphylaxis to Penicillin: Harvesting Insights From the Food and Drug Administration's Adverse Event Reporting System

There is a gap in knowledge regarding the contemporary epidemiology of penicillin-associated anaphylaxis.

To assess whether penicillin antibiotics (PAs) had higher reporting odds of anaphylaxis compared with other medications, patterns of anaphylaxis reports attributed to specific PAs, and the frequency of reported mortality associated with anaphylaxis using pharmacovigilance methods using the Food and Drug Administration Adverse Event Reporting System database.

We included patients in the Food and Drug Administration Adverse Event Reporting System with reported anaphylaxis to PAs from 2013 to 2023 in this cross-sectional study. Reporting odds ratios and proportional reporting ratios were used to determine whether specific PAs had higher reporting odds of anaphylaxis.

Among a total of 20,815,425 adverse events and 48,637 reports of anaphylaxis, there were 3,176 reports of anaphylaxis to PAs. Compared with other medications, all PAs had higher reporting odds of anaphylaxis. Compared with all other PAs, there were disproportionality signals for reported anaphylaxis to amoxicillin-containing medications (reporting odds ratio, 1.97; 95% CI, 1.82-2.14) and "unspecified" PAs (reporting odds ratio, 1.77; 95% CI, 1.44-2.19). We observed a higher proportion of anaphylaxis reports to all PAs (4.5%) from reports outside the United States (US) compared with reports from the US (2.3%, P < .0001). US reports demonstrated higher reporting odds for anaphylaxis to nonaminopenicillins and piperacillin-tazobactam, whereas non-US reports demonstrated higher reporting odds for amoxicillin-containing medications. There were 139 reports of anaphylaxis to PAs associated with death.

PAs had higher reporting odds of anaphylaxis compared with all other medications in the Food and Drug Administration Adverse Event Reporting System database. We observed regional differences in reporting odds to specific PAs when comparing US and non-US reports. Fatalities reported following anaphylaxis were rare.