Patient leaflet with Nature Throid

Does anyone know what this means, please, on the Patient Leaflet in my pack of Nature Throid? I'm taking vitamin k with my vitamin D so I found this warning baffling:

'Drug Interactions: oral anticoagulants: Thyroid hormones appear to increase catabolism of vitman k- dependent clotting factors. If oral anticoagulants are also being given, compensatory increases in clotting factor synthesis are impaired. Patients stabilised on oral coagulants should be watched very closely when thyroid replacement treatment is started. If a patient is truly hypothyroid, it is likely that a reduction in anticoagulant dose will be required. No special precautions appear to be necessary when oral anticoagulant therapy is begun in a patient already stabilised on thyroid replacement therapy.'

I'm not taking anticoagulants. I am taking vitamin k to make sure vitamin D gets into my bones not soft tissues.

I cannot decipher the warning, although I realise that 'catabolism' means breaks down..



9 Replies

  • Are you taking vitamin K? Or vitamin K2? The one you should be taking is K2. I don't think that K2 has any effect on clotting - but I really, really must stress that I am not sure of my facts.

    Edit : To future readers - ignore the last sentence in my post and read gabkad's answers below.

  • Thanks, Humanbean. It's life Extension Super K with advanced K2 complex. Says for bone-health on bottle. I read about K2 in Kate Rheaume-Bleue's book, Vitamin K2 And The Calcium Paradox.

    You're quite right; I should have made it clear.


  • Dr. Leon Schurgers who was interviewed recently said that Vitamin K2 does affect those who are on anticoagulants. Someone posted this on the week-end.

  • Yes, it does, Gabkad, thank you. My problem isn't that. It is rather: should I continue to take the VitK2 if I decide to stay on the Nature Throid? I have never taken anticoagulants so that bit doesn't worry me.

    Many thanks,


  • Keep taking them. I take 5 mg Vitamin K2 twice per week for same reasons as you do. Nothing to do with thyroid medications.

  • Thank you very much, Gabgad. Also for your advice earlier this year regarding h pylori. I had a test and I didn't have it.


  • I think it's saying that if you take thyroid hormones with Warfarin it results in interference with the body's ability to regulate use of vitamin K. So if you don't take warfarin (or a similar anticoagulant) there's not a problem.

  • Thanks so much, Jazzw. Very reassuring.


  • Hi All thyroid meds affect anticoagulation so if on them take care to check the INR.


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