[Adverse events to antibiotics in inpatients of a university hospital].

OBJECTIVE Antibiotics are the most common drugs causing adverse events and they lead to problems to patients and additional costs of the health system. The aim of the study was to evaluate the occurrence of adverse events to antibiotics in inpatients of a hospital. METHODS An extensive drug monitoring was conducted in adult inpatients taking antibiotics in the city of Maringá, Southern Brazil, from September 2002 to February 2003. Variables related to medications used, especially those related to antibiotic use and adverse events, were studied. Based on criteria for adequate antibiotic use, the observed events were classified as adverse events, medication errors and near-misses. For the analysis of causality between drug administration and event occurrence Naranjo algorithm was used. RESULTS A total of 87 patients were studied and 91 adverse events were identified: three (3.3%) adverse drug reactions; seven (7.7%) medication errors; and 81 (89.0%) medication near-misses. Adverse drug reactions were related to the use of quinolones and likely according to Naranjo algorithm. The seven medication errors were associated to four inadequately prescribed doses and three drug interactions. CONCLUSIONS The study results indicate that an inadequate knowledge on antibiotics or lack of information about the patient at the time of prescription were the major factors involved in the occurrence of adverse events.