Introduction: Visible hematuria is not rare in patients on anticoagulant therapy. There is no consensus regarding the diagnostic approach for them; some authors suggest restricted volume of diagnostic procedures because of the low number of urological etiology found. Some antibiotics have been reported to potentiate the effect of oral anticoagulants.
Material and methods: The study addresses the need for urological assessment of patients on anticoagulation therapy and the possible role of some drugs administrated simultaneously with an oral anticoagulant, for the onset of macroscopic hematuria. Patients hospitalized with hematuria, both with or without anticoagulation therapy, were investigated and followed up.
Results: The onset of hematuria depends on the monitoring of oral anticoagulation. INR (International Normalized Ratio) value corresponds with the probability of non-urological etiology, where INR>4 carries relatively low risk for urological and malignant etiology. Some antibiotics may influence the anticoagulation effect, so INR value may be elevated and hematuria may occur.
Conclusions: Anticoagulation therapy should be administrated carefully and individually. The risk of urological etiology of hematuria is lower in patients on oral anticoagulants (especially when INR >4), however, it is not zero.
Keywords: International Normalized Ratio; anticoagulants; diagnostic volume; hematuria.