Efeito da Vitamina K em indivíduos submetidos à terapia de anticoagulação com varfarina: uma revisão narrativa

Abstract

The use of vitamin K antagonists, such as warfarin, is common in the treatment of thromboembolic phenomena, acting as an anticoagulant by interfering with the vitamin’s interconversion cycle. However, vitamin K intake, whether through diet or supplements, may impact drug efficacy, making dietary adjustments necessary to stabilize therapy. Objective: This study aims to review publications on the effects of vitamin K in patients undergoing warfarin therapy, seeking to clarify recommendations for micronutrient intake and its impact on coagulation assessment markers in this population. Methodology: This is an integrative review conducted using data sources such as the Medical Literature Analysis and Retrieval System Online (MEDLINE) via the PubMed interface, Cochrane, and Google Scholar, in Portuguese and English, using keywords like “Vitamin K,” “Warfarin,” and “INR (International Normalized Ratio)” combined with Boolean operators. Study screening and selection were performed using the Rayyan® tool, resulting in eleven studies included. Results: The studies showed that regular vitamin K intake can lead to INR stabilization. Daily supplementation (150-200 µg) was beneficial for patients with unstable control, reducing INR variability and increasing time within the therapeutic range. Additionally, a diet rich and consistent in vitamin K proved effective in stabilizing INR in patients with regular intake. Conclusion: INR stability is essential in anticoagulation management. Supplementation or dietary adjustments with vitamin K should be personalized, considering the patient's profile and monitored by a multidisciplinary team to maximize benefits and reduce risks associated with anticoagulation therapy.