Objectives. To investigate the incidence of patients being inappropriately labelled as allergic to opioid medications and to assess the effect that this label may have had on the subsequent prescribing of opioids.
Methods. A study was conducted on patients admitted to Toowoomba Hospital over a three month period as to their perceived opioid allergy status. In addition to medication history interview, pharmacists recorded data on any claimed drug allergy attributed to opioid medications. Events were classified depending on the probability of the event being an allergic or immunological drug reaction. Medical records and medication charts of identified patients were checked to determine if allergy status had any effect on opioid prescribing.
Results. Thirty patients reported an opioid allergy. Morphine and codeine were most commonly implicated, with nausea and vomiting the most likely adverse events. Six patients were classified as high probability of allergic reaction, although anaphylaxis wasn’t reported. Most allergy documentation was incomplete, with the nature of reaction seldom recorded. Despite a ‘supposed’ opioid allergy, 70% of patients were prescribed subsequent opioids. Of the six patients in the high probability group, four were prescribed opioids. Three received alternate opioids without incident, while nurses refused to administer the same previously implicated drug to the fourth patient.
Conclusion. Opioid prescribing did not appear to be influenced by a reported allergy. Ignoring ‘real’ allergies, however rare, may put patients at risk of severe consequences. Staff must be educated regarding the importance of recording accurately and thoroughly the specifics of patients’ medication allergies and its importance in future safe prescribing.
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