Aim To investigate factors that impact upon compliance with antibiotic regimens among patients in the emergency department (ED).

Methods This was a prospective cohort study of patients prescribed antibiotics in a single ED. Patients were identified by witnessing the consultation, medical records and ‘after hours’ prescriptions. Data were collected on demographics, presenting condition, usual medications, antibiotic regimen and instructions given. At follow up 7 days later, data were collected on compliance, antibiotic cost and packaging, side effects, difficulty with the regimen and other medical advice sought. The association between compliance and predictor variables was examined using multivariate logistic regression.

Results 192 patients had complete data for analysis. Using two definitions of compliance (100% and ≥80% of prescribed doses), antibiotic compliance was 80% and 93%, respectively. Unemployment was negatively associated with 100% compliance (OR 0.24, 95% CI 0.07 to 0.78) and taking ≥2 regular medications was positively associated with 100% compliance (OR 4.2, 95% CI 1.2 to 15.5). No variable was associated with compliance at the ≥80% level. However, patients who were female, employed, born overseas, better educated, prescribed a single antibiotic or who had a longer course, a single dose per day, medication rather than a prescription and tablets rather than capsules tended to be more compliant. Forgetfulness, improvement of symptoms and side effects were the main reasons for non-compliance.

Conclusion Compliance was better than reported elsewhere. The good compliance among patients taking ≥2 regular medications may relate to their established medication routines. Scope exists for ED pharmacists to intervene with patients ‘at risk’ of poor antibiotic compliance.