[Outpatient medication usage during hospitalization]

To study the frequency and circumstances of patients' use of outpatient medications prescribed by their GP during hospitalization and to assess means of reducing this use.

A prevalence study of medication use was conducted at Saint Joseph's Hospital in Paris. On one day, we used a specific questionnaire to interview 151 patients in 11 different units about the type and amount of medications they had brought with them to the hospital and the type and amount they had used.

Overall, 61% had brought their prescription medication with them, and 36% had used some of it, sometimes without informing the medical staff. In 75% of these cases, these drugs were available from the hospital pharmacy.

Possible corrective steps include both technological improvements (computerized prescription) and organizational measures: systematic inquiry about and consideration of outpatient prescriptions at admission, use of validated prescription/substitution aids (Comedims), and patient information and education about drug substitutions and interactions.