Levetiracetam may reduce anticoagulation effect of rivaroxaban
Levetiracetam, a commonly used medication to prevent seizures, may reduce the anticoagulation effect of oral rivaroxaban in humans. As such, clinicians should measure direct oral anticoagulant plasma levels during treatment. A case report is published in Annals of Internal Medicine.
Clinical guidelines recommend the use of levetiracetam with oral anticoagulants because animal studies suggest that the anti-convulsant acts as a P-glycoprotein inducer to reduce rivaroxaban plasma levels. However, not everyone is convinced that levetiracetam should be avoided in patients receiving rivaroxaban because there is little or no published evidence describing this interaction in humans.
Researchers from the University of Prugia, Perugia, Italy, report the case of a 69-year-old man who was taking rivaroxaban for atrial fibrillation and started to experience seizures in his right frontal lobe, for which he was prescribed levetiracetam. Several months later, he was clinically diagnosed with recurrent transient ischemic attacks. The clinicians measured his rivaroxaban plasma levels to determine if low levels would explain the transient ischemic attacks and then changed levetiracetam with lacosamide, an anticonvulsive not interfering with P-glycoprotein. Repeated measurement of rivaroxaban plasma levels showed a clinically relevant interaction between levetiracetam and rivaroxaban, where the drug reduced plasma levels, with a particularly strong and long-lasting effect on trough levels.
The clinicians believe that this interaction is clinically important but caution that their study was limited and they did not measure P-glycoprotein activity in the patient.