Aim of the study is to investigate whether the influence of drugs inducing of CYP 3A4 isoenzyme of CYP450 and P-gp transporter significantly affect plasma levels of DOACs in patients with NVAF and venous thromboembolism

Aim of the study is to investigate whether the influence of drugs inducing of CYP 3A4 isoenzyme of CYP450 and P-gp transporter significantly affect plasma levels of DOACs in patients with NVAF and venous thromboembolism. Also the difference between DOACs inducing both CYP3A4 and P-gp transporter (rivaroxaban and apixaban) and DOACs inducing the P-pg transporter only will be investigated. Thriomboembolic and bleeding events during the study duration will be registered and correlated to the measured DOAC plasma levels.

Inclusion Criteria:

• patients with a diagnosis of nonvalvular atrial fibrillation or a diagnosis of venous thromboembolism who are taking direct oral anticoagulants according to current guidelines and concomitant enzyme inducers antiepileptic drugs; patients available for a 12 months follow up; patients who can sign informed consent

Exclusion Criteria:

• patients who stop antiepileptic drugs; age <18 yo patients not willing to perform blood draw or not available for a 12 months follow up; patients who cannot sign informed consent

For sample size calculation we used data from a pilot study on 10 patients and controls. A significant difference of subject frequency with DOAC plasma concentrations below the expected peak value, respectively 35% and 10% for patients using or not using EI/AED, was defined as the primary end-point. A sample size of 40 subjects in each group was estimated for 80% power and alfa = 0.05