Documentation of adverse drug reactions to opioids in an electronic health record

Background: Allergy to opioids is the second most common drug allergy label in electronic health records (EHR). Adverse drug reactions (ADR) to opioids cause significant morbidity and contribute to healthcare costs, while incorrect opioid allergy labels may unnecessarily complicate patient management. Aims: To examine the documentation of opioid ADR in a large-scale hospital-based EHR. Methods: A cross-sectional retrospective review of EHR documentation of opioid ADR at four public hospitals in South Australia was conducted. Data were extracted from all ADR entries including the reported allergen, ADR category (allergy or intolerance) and reaction details. Expert criteria were used to determine consistency of ADR categorisation as allergy or intolerance. Results: Of 86 727 unique ADR reports, there were 13 781 ADR to opioids with most being entered as allergy (n = 8913, 64.7%) rather than intolerance (n = 4868, 35.3%). The most commonly documented reactions were nausea/vomiting (n = 3912, 28%), rash (n = 647, 5%), itch (n = 642, 5%) and hallucinations (n = 527, 4%). There were 362 (3%) ADR labels of anaphylaxis. Of those ADR containing a reaction description (n = 11 868), 89% of reports entered as allergy had a reaction description that was consistent with intolerance and 8% of the entered intolerances had descriptions consistent with allergy when assessed using predefined criteria. Conclusions: This large EHR-based study demonstrates the high rate of opioid ADR labels in EHR. The majority of these labels were for symptoms suggestive of pharmacological intolerance. Reactions consistent with true allergy were uncommon. Systematic review of ADR by a dedicated clinical service would improve the accuracy of documentation.