A patient with a mechanical valve receives rifampicin-containing treatment and needs a substantially increased warfarin dose. Rifampicin is then

Question

A patient with a mechanical valve receives rifampicin-containing treatment and needs a substantially increased warfarin dose. Rifampicin is then stopped. What anticoagulation hazard should be anticipated?

Accepted Answer

The INR can rise as enzyme induction wanes, so warfarin requires frequent reassessment and prompt dose reduction

Answer

The INR becomes uninterpretable and must be replaced by an anti-Xa assay

Answer

The INR will remain permanently low because rifampicin irreversibly induces CYP enzymes

Answer

Flucloxacillin prevents any post-rifampicin change in warfarin requirement

Answer

Warfarin absorption will cease for 6 weeks after the last rifampicin dose

Rifampicin-Warfarin Interaction — SCE Infectious Diseases MCQ

A patient with a mechanical valve receives rifampicin-containing treatment and needs a substantially increased warfarin dose. Rifampicin is then stopped. What anticoagulation hazard should be anticipated?