Determinants of initiation, implementation, and discontinuation of amoxicillin by adults with acute cough in primary care

Aim: To investigate the determinants of adherence to amoxicillin in patients with acute lower respiratory tract infection. 

Materials and methods: Three European data sets were used. Adherence data were collected using self-reported diaries. Candidate determinants included factors relating to patient, condition, therapy, health care system/provider, and the study in which the patient participated. Logistic and Cox regression models were used to investigate the determinants of initiation, implementation, and discontinuation of amoxicillin. 

Results: Although initiation differed across samples, implementation and discontinuation were similar. Determinants of initiation were days waited before consulting, duration of prescription, and being in a country where a doctor-issued sick certificate is required for being off work for 7 days. Implementation was higher for older participants or those with abnormal auscultation. Implementation was lower for those prescribed longer courses of amoxicillin (≥8 days). Time from initiation to discontinuation was longer for longer prescriptions and shorter for those from countries where single-handed practices were widespread. 

Conclusion: Nonadherence to amoxicillin was largely driven by noninitiation. Differing sets of determinants were found for initiation, implementation, and discontinuation. There is a need to further understand the reasons for these determinants, the impact of poor adherence to antibiotics on outcomes, and to develop interventions to improve antibiotic use when prescribed.