Blood thinners and vitamin k supplements

[Goldrill]

My dad had a couple of TIAs a few years ago and has been on warfarin since. At the end of last year, he had a minor stroke and the doc says he has atrial fibrillation; they're just in the process of switching him to a different blood thinner.

My mum mentioned this evening that they both started taking a fair dose of vitamins d & k "as recommended by doctors during covid ". Dad has not mentioned this to his doctors, including the one changing his blood thinner at the moment.

My mum was clearly annoyed with me for questioning her on whether dad's doctor knows about this and I don't want to cause any upset, but I am pretty sure vit k and warfarin are working in opposite directions.

I don't have any idea how big a deal this is and whether I should risk further upsetting my mum by raising it again. Equally really don't want to leave it and have nagging worry that the recent stroke might be because the warfarin wasn't effective.

Anyone able to give me a feel for how serious this is, please?

Unlikely I think. You have regular blood tests when on warfarin which check that the warfarin is doing its job, ie that your INR is in range. If the extra vit K had impacted on warfarin, this would have showed up on the blood result, and the warfarin dose changed (probably increased) if needed, by the clinic.

He should definitely mention to doctors so they can advise re vit k supplements. But as changing drug, new one unlikely to be a vit k antagonist.

Not a medic, but on warfarin. Hope that helps

Well I am a medical professional, it is a problem and they do indeed antagonise one another and this may well be a problem with whatever other blood thinner they put him on. He absolutely needs to mention this to his Drs.

Thank you both very much for responding. I will have a chat with my mum and hope it comes across as intended.

It may be an issue but also if he suddenly stops put his warfarin levels out of whack. I’d suggest he talks to the GP before stopping and have a plan for extra blood tests.