Represcription of penicillin after allergic-like events

Andrea J. Apter, Judith L. Kinman, Warren B. Bilker, Maximilian Herlim, David J. Margolis, Ebbing Lautenbach, Sean Hennessy, Brian L. Strom

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


Objective: We sought to determine the frequency of represcription of penicillin to individuals with penicillin allergy and the risk of a second reaction in those who had a previous reaction. Methods: A retrospective cohort study was conducted within the UK General Practice Research Database. All patients who had received a prescription for penicillin were identified. Within that source population, records of patients who had received at least 2 prescriptions for penicillin at least 60 days apart were selected and examined for allergic-like (hypersensitivity) events on the day of or within 30 days after a prescription. Results: At least one prescription for penicillin was given to 3,375,162 patients. Of 6212 (0.18%) patients who experienced an allergic-like event after the initial prescription, 48.5% were given a second prescription compared with 59.8% of those without an initial allergic-like event (risk ratio, 0.81; 95% CI, 0.79-0.83). Two or more prescriptions for penicillin were given to 2,017,957 patients. Three thousand fourteen (0.15%) patients experienced an allergic-like event after the first prescription, and 57 (1.89%) of those had another event after the second prescription. The unadjusted odds ratio of an allergic-like event after the second prescription for those who experienced an allergic-like event after the first prescription, compared with those who had no initial event was 11.2 (95% CI, 8.6-14.6). Adjusting for confounding had no substantive effect on this result. Conclusion: The risk of an allergic-like event after penicillin is markedly increased in those who have had a prior event, although the absolute difference is small (1.72%). Represcription of penicillin to such patients is more frequent than anticipated.

Original languageEnglish (US)
Pages (from-to)764-770
Number of pages7
JournalJournal of Allergy and Clinical Immunology
Issue number4
StatePublished - Apr 2004

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology


  • Adverse drug reaction
  • Anaphylaxis
  • Angioedema
  • Drug allergy
  • Drug hypersensitivity
  • Penicillin
  • Toxic epidermal necrolysis
  • Urticaria


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