V. Rollason, N. Vernaz, L. Adlere, P. Bonnabry, J. A. Desmeules; Geneva University Hospitals, Geneva 14, Switzerland

BACKGROUND: As omeprazole, the proton-pump inhibitor esomeprazole is a strong CYP2C19 inhibitor. A pharmacokinetic interaction with the antiplatelet drug clopidogrel, by inhibiting its bioactivation, could translate into antithrombotic inefficacy. Contradictory guidelines as to the co-prescription of these two drugs exist, several recommending at least a 10-hour separation of dosing. We evaluated the prescribing practices of clopidogrel and esomeprazole in our university hospital by analyzing the doctors’ medical orders and the nurses’ administration schedules in order to evaluate the quality of this co-prescription.
METHODS: Doctors’ medical orders and nurses’ administration schedules were analyzed separately from January 2013 to April 2014. In our computerized provider order entry system (CPOE), doctors can specify or not when the medication has to be taken (morning, lunchtime, evening, bedtime) and nurses then create the administration schedule.
RESULTS: 57% (933/1649) of patients under clopidogrel had a co-prescription of esomeprazole during the study period. Among them 15% had a medical order separating the administration of more than 10 hours, 16% a concomitant prescription, 5% 40 mg esomeprazole twice daily and 64 % no clear information as to when to administer the drugs. Surprisingly we found a higher rate of patients (39%) having a nurse’s schedule of more than 10 hours.
CONCLUSION: The medical order’s information time frame should be mandatory in order to improve the transmission throughout the whole information system of our CPOE and allow a separating of clopidogrel-esomperazole co-prescription avoiding drug-drug interactions. Nurses take the initiative to separate the co-prescription when this is not clearly defined by the medical orders.