Safety Profile of Esomeprazole: Results of a Prescription-Event Monitoring Study of 11 595 Patients in England

Objective: Esomeprazole, the S -isomer of omeprazole, was launched in the UK in September 2000. The first proton pump inhibitor, omeprazole, has been marketed in the UK for over 10 years. However, the adverse event database of newly marketed drugs is limited, and it is only after widespread clinical use that the adverse effect profile of a drug is ascertained more comprehensively. This study aims to monitor the safety of esomeprazole prescribed in the primary care setting in England using prescription-event monitoring (PEM). Methods: A postmarketing surveillance study using the observational cohort technique of PEM. Patients were identified from dispensed prescriptions for esomeprazole issued by general practitioners between September 2000 and April 2001. Questionnaires (‘green forms’) requesting clinical event data on these patients were sent to prescribers approximately 6 months after the date of the first dispensed prescription for each individual patient. Incidence densities (IDs), expressed as the number of first reports of an event/1000 patient-months of exposure (PME), were calculated. Significant differences between IDs for events reported in the first month (ID 1 ) and the following 5 months (ID 2–6 ) of exposure were regarded as potential signals. Other methods for signal detection such as medical evaluation of selected events and evaluation of reasons for stopping were also applied. Results: Green forms containing clinically useful information for 11 595 patients (median age 56 years; 53.2% female) were received. Diarrhoea was the event with the highest ID 1 in month 1 (8.0 per 1000 patient months of exposure). Adverse events that occurred significantly more often in the first month of treatment with esomeprazole compared with months 2–6 included diarrhoea, nausea/vomiting, abdominal pain, dyspepsia, headache/migraine, intolerance, malaise/lassitude, pruritis, unspecified adverse effects and abnormal sensation. Conclusions: The safety profile of esomeprazole was consistent with the prescribing information and experience reported in the literature.