[Drug-drug interactions in patients from an internal medicine service].
OBJECTIVE
Drug interactions are the cause of serious adverse reactions, the incidence and morbi-mortality of which are not yet well established. The aim of this study is to carry out an initial estimate of drug interactions in an internal medicine service and to look at any factors associated with their appearance.


METHODS
A prospective study was carried out with 120 patients randomly selected from a total of 376 patients admitted to an internal medicine service over a period of three months (February-April 2007). A protocol was designed on an ad-hoc basis to record the interactions.


RESULTS
It was observed that 43% of the patients had at least one potential adverse drug interaction and 14% showed associated adverse interactions. The drug with the highest implications in pharmacokinetic interactions was omeprazole when prescribed with acenocoumarol, phenytoin and digoxin. The most significant pharmacodynamic interactions were with associations between NSAID and saluretic-diuretics, insulin and beta-blockers, and aspirin and prednisone. The number of interactions did relate to the number of prescriptions (p < .001), however this was not the case for gender, age and co-morbidity.


CONCLUSIONS
Drug interaction is a serious clinical problem which requires the availability of more in depth information and medical attention.
Ibáñez
A
A
Servicio de Farmacología Clínica. Hospital Universitario San Cecilio. Granada. España.
Alcalá
M
M
García
J
J
Puche
E
E
D000368:Aged; D004347:Drug Interactions; D005260:Female; D006748:Hospital Departments; D006801:Humans; D007388:Internal Medicine; D008297:Male; D011446:Prospective Studies