Asian people with atrial fibrillation should not be prescribed low-dose rivaroxaban as it puts them at increased risk of ischaemic stroke, a Taiwanese study suggests.

The finding should act as a message to doctors not to prescribe lower doses of the drug in these patients because of bleeding risks, the authors say.

The retrospective analysis included more than 2200 AF patients treated with the drug — some who were taking it at recommended doses while others were on lower off-label doses appropriate only for patients with reduced kidney function — at Taipei Veterans General Hospital.

It found those on an off-label 10mg dose had nearly three times the risk of ischaemic stroke compared with those on recommended doses over more than two years’ follow-up.