RESUMEN
INTRODUCTION: Capecitabine is an oral anticancer drug which can cause some adverse reactions and the great challenge for its use is to ensure the medication adherence. The aim of this study was to analyze adverse reactions and adherence to capecitabine in patients with gastrointestinal cancer. METHODS: A prospective study was performed in a tertiary teaching hospital in Brazil. Outpatients undergoing capecitabine treatment for colorectal or gastric cancer were followed for three cycles of treatment. Patient demographic and clinical characteristics data were collected. Adverse reactions were analyzed using Common Terminology Criteria for Adverse Events (CTCAE) v.4. Adherence to capecitabine were evaluated using Morisky-Green and MedTake tests. Statistical analysis was conducted using Chi-square, Fisher's exact and McNemer tests. RESULTS: One hundred and four patients were enrolled in this study, with a mean age was 58.5 ± 10.9 years; 51.0% were men and 51.0% Caucasian. Nausea and diarrhea were the most frequently reported adverse reactions (82.7% and 62.5%, respectively), followed by vomiting (54.8%), fatigue (54.8%), and hand-foot syndrome (53.9%). Nausea and diarrhea were also the most severe adverse reactions. Most patients were adherent to capecitabine in all cycles of treatment using the Morisky-Green test. Adherence increased significantly between cycle 1 and cycle 2 by MedTake test (p < 0.001). Some demographic and clinical characteristics were associated with adverse reactions (e.g., age and nausea, gender and nausea and vomiting) and capecitabine adherence (e.g., marital status and educational level) as well as some adverse reactions were associated with capecitabine adherence (hand-foot syndrome and nausea). CONCLUSIONS: Clinical oncology pharmacists must provide patient information on the correct use of capecitabine, manage adverse reactions, and monitor adherence to treatment. Strategies to prevent non-adherence to capecitabine must be adopted to ensure the success of pharmacotherapy.