RESUMEN
BACKGROUND: Adverse Drug Reactions (ADR) are a major cause of morbidity and mortality worldwide. In spite of this, ADR are largely underreported and unrecognized. PURPOSE: Identify and characterize ADR related admissions to our internal medicine ward using a proactive multidisciplinary pharmacovigilance approach. METHODS: Within 24 hrs of admission 1045 patients admitted to the Internal Medicine Ward between August 2010 and February 2012 were screened for possible or probable ADR related admissions. RESULTS: Probable ADR accounted for 112 of 1045 admissions (10.7%, 95% Confidence Interval [CI]: 8.8-12.6%), of which only 16 (14.3%) were classified as unavoidable. NSAIDs were the drug group more commonly implicated in probable ADR-related admissions (17.0%), followed by antiplatelets (16.1%). In-hospital mortality of patients admitted due to probable ADR was 8.0% (95% CI: 2.9-13.1%). During this study period, 6% of internal medicine ward and 4% of critical care unit beds were occupied by patients with probable ADR. The estimated cost of care of these patients was 641,000 US dollars (USD). CONCLUSION: ADR are a frequent reason for admission to an Internal Medicine Ward in Argentina. The culprit drugs and interactions are similar to those reported in the literature. The cost is substantial and most of the ADR are potentially avoidable.