[Drug interactions: study of 409 prescriptions at the time of discharge from geriatric hospitalization]

In order to specify the frequency and the potential consequences of drug interactions in the elderly, we retrospectively analysed 409 discharge prescriptions. The possibility of drug interactions was screened out for each prescription in the software version of the Vidal drug compendium. It appears that prescriptions are mainly adapted to the elderly with respect to posology and pharmacokinetics. Potentially dangerous drug interactions ('contraindicated' or 'unsuitable' associations) were found in 6 per cent of prescriptions; after careful assessment, this frequency decreased to less than 1 per cent. The most common orthoergic side effects were sedation (15 per cent) and hypotension (14.5 per cent). This study points out the multiplicity of criteria to be considered in order to prevent drug interactions, and the gaps in available software.