Agreement among four drug information sources for the occurrence of warfarin drug interactions in Brazilian heart disease patients with a high prevalence of Trypanosoma cruzi infection

• Published in: European journal of clinical pharmacology 2013-04, Vol.69 (4), p.919-928
• Main Authors: Martins, Maria A. P., Ribeiro, Daniel D., Nobre, Vandack A., Pereira, Fabiana R., César, Cibele C., Rocha, Manoel O. C., Ribeiro, Antonio L. P.
• Format: Article
• Language: English
• Subjects: Adverse Drug Reaction Reporting Systems - statistics & numerical data; Anticoagulants - administration & dosage; Anticoagulants - adverse effects; Anticoagulants - therapeutic use; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Brazil - epidemiology; Cardiovascular disease; Chagas Disease - blood; Chagas Disease - complications; Chagas Disease - drug therapy; Chagas Disease - epidemiology; Cross-Sectional Studies; Drug Interactions; Drug therapy; Female; Heart; Heart Diseases - blood; Heart Diseases - complications; Heart Diseases - drug therapy; Heart Diseases - epidemiology; Hemorrhage - chemically induced; Hemorrhage - epidemiology; Hospitals, University; Human protozoal diseases; Humans; Infections; Infectious diseases; Male; Medical sciences; Middle Aged; Outpatients; Parasitic diseases; Pharmacoepidemiology and Prescription; Pharmacology. Drug treatments; Pharmacology/Toxicology; Polypharmacy; Prevalence; Protozoal diseases; Trypanosoma cruzi - isolation & purification; Trypanosomiasis; Warfarin - administration & dosage; Warfarin - adverse effects; Warfarin - therapeutic use
• ISSN: 0031-6970; 1432-1041
• DOI: 10.1007/s00228-012-1411-6

Purpose The aim of this study was to assess the agreement of four renowned interaction lists on potentially severe warfarin drug interactions (DI) in outpatients at a university hospital in Brazil, specifically in subgroups of Trypanosoma cruzi -infected and non-infected patients and those with previous bleeding episodes. Methods This was a cross-sectional study in which adult outpatients with heart disease and indications for chronic warfarin use were enrolled. The occurrence of potentially severe warfarin DI was evaluated based on the lists provided by three compendia, i.e., Drug Interaction Facts (DIF), Drug Interactions: Analysis and Management (DIAM) and DRUG-REAX, and by the World Health Organization (WHO) Model Formulary. A kappa coefficient was used to calculate the agreement among the sources. Results A total of 280 patients were studied. Most patients were female (54.6 %) with an average age of 56.8 (standard deviation 13.1) years. The agreement among the four sources was fair (Fleiss’ kappa coefficient = 0.295). T. cruzi -infected individuals were less likely to have severe warfarin DI than non-infected patients ( p