Drug interactions: a prospective pilot study in primary health care

The present prospective pilot study investigated putative drug interactions in primary health care. Among 110 outpatients, 50 were treated with more t han one drug (maximum = 10). Among these 50 prescription forms, 21 concerne d at least one drug interaction, with a total of 47 different drug interact ions, Most of them (94 pet cent) were explained by a pharmacodynamic mechan ism. They were classified as 'requiring use precautions' (64 per cent), 'to be taken into account' (25 per cent) or 'inadvisable' (11 per cent). None of them was 'contraindicated'. Most often the drugs involved were diuretics , converting enzyme inhibitors or non-steroidal antiinflammatory drugs. Dru g interactions, which concern around one in five prescription forms, remain an important topic in Clinical Pharmacology.