Anticoagulant activity of oral rivaroxaban in healthy dogs

Therapeutic monitoring of rivaroxaban in dogs using thromboelastography and prothrombin time

“…One dog (dog E in Figure ) showed relatively low increments in PT and TEG parameters as well as anti‐Xa concentration after drug administration. These results are similar to those of a previous study that reported that interindividual variability was moderate to large in 24 healthy Beagles . We speculate that individual monitoring of rivaroxaban in dogs could be beneficial, unlike in humans, and appropriate individual dosage adjustment could be achieved by PT and TEG monitoring according to the study.…”

“…Previous studies in dogs have reported a mild to moderate interindividual variability, and the dosage could be appropriately adjusted by interpreting the PT results in a clinical setting . Although the exact reason is not known, interindividual variability also was detected in our study.…”

“…We selected 3 hours post‐administration as the peak time point according to previous studies in humans . A recent study reported a peak time point of 1.5‐2 hours after dosing in dogs . However, the dogs in our study were not allowed to fast during the study period; thus, the peak time may have been slightly delayed because food can interfere with the absorption of rivaroxaban, leading to delayed peak times of 0.5‐1.5 hours compared to those in the fasted state .…”

“…In addition, the drug effect was detected 3 hours after dosing in various tests but not 8 or 12 hours after dosing using the point‐of‐care PT and TEG devices. This result was similar to results of a previous study . Three dogs each in the 0.5 and 1 mg/kg dosing groups were given rivaroxaban once daily for 3 consecutive days and were monitored.…”

“…In our study, dosages above 2 mg/kg were appropriate for healthy dogs to achieve an anti‐Xa concentration >140 ng/mL at the peak time. This dosage was similar to the appropriate dosage regimen suggested in a previous report . Choosing the lowest dosage to achieve therapeutic ranges of plasma rivaroxaban concentrations could decrease the total cost of drug required for treatment.…”