Methotrexate and low B12 levels


First time on here but wondering if anyone has any advice. I've been taking methotrexate for over a year ( plus the frolic acid) without any problems. My tongue however, has started to feel sore and I'm feeling increasingly dizzy and faint. My last blood test 2 weeks ago said I needed to go back to test again in 4 weeks as B12 was low. Does this ring any bells for anyone? Any advice?

19 Replies

  • I have to ask, are you taking tablet form MTX or injections? Injections should reduce the dizziness and faintness, but as for the sore mouth, I have that too. I shall look into B12 in case it has some good effect for me. Thanks for bringing this up. x

  • I take 4 2.5mg tablets every week. Quite a low dose really but up to this, I haven't had any side effects so the rheum nurse didn't want to increase the dose.

    Thanks for your reply

  • I take a B12 supplement just as a matter of course. My doctor recommended it to help with the fatigue. Come to think of it, I've missed a couple days, and my mouth is increasingly sore. Hmm, I hadn't thought of it until now. Thanks for the post.

  • Thanks for your reply

    Are you also on methotrexate and did you have similar symptoms? It's the faint/ dizziness that's worrying me the most.

  • Does B12 help the fatigue? For me, fatigue is the worst part of RA.

  • I hope so. Will be discussing with my doctor.

  • Yes, I'm on mtx and leflunomide and hydroxyquine right now. I'm having dizziness and faintness, too (like my brain is only loosely attached to my skull). I just did a little google search, and it looks like mtx decreases the bio-availability of B12, and the symptoms of deficiency include light-headedness and sore tongue. It's amazing to me how these things intertwine! I'm going to up my supplement a bit and see if it helps, I'll keep you posted!


  • Thanks Bats.

    That makes sense to me now. Did you buy the supplements yourself or have them prescribed? I'll do my bloods in 2 weeks and go see my doctor.

    I hope your dizziness/ faint spells get better soon.

    Lovely to chat with people with same problem.

    Forgot to mention that I'm also have heart palpitations. Must also be connected so watch out for those.


  • My doctor recommended the dose (1000 iu), but I just picked them up. I'd check with your gp or rheumy before adding anything to your regime, though.

  • I got low B12 levels prior to my coeliac disease diagnosis. Its a really common indicator of malabsorption problems with things like coeliac.

  • I had very low b12 levels a year before being diagnosed with RA, it led to me falling over backwards and showing some very strange behaviour, also very sore swollen tounge and mouth and splits to the side of my mouth. The neurologist I saw at the time said it was common in lots of auto immune problems. I now have B12 injections every month and can tell I am late in doing it as I get very dry and sore mouth . I never found that tablets worked but the sub lingual drops were better, but injections tend to work best. It doesn't help that I tend to be mostly vegan.

  • This is so helpful. I will ask about the injections and see if they can do them at my doctors. They are reluctant to even prescribe MTX and said they have only been doing it for 2 years. They really wanted me to visit the hospital each time.

    Thanks for the reply and I hope you keep well.

  • my rheumatology consultant prescribes mine. The prescription goes straight to the company that supplies them and they deliver them to my home. Are you in the UK? Systems are usually different in other countries. Here in the UK, GPs can't prescribe drugs like Methotrexate. A consultant has to prescribe, then if it is a drug in tablet form, they will instruct your GP to continue to give you a prescription for them until further notice.

  • Yes I'm in the Uk. Will deff speak to my GP about B12 supplements. My repeats are with my doctor but he can't up or lower my dose.

    Thanks for your reply. These have been so helpful for me.

  • When I found out I had RA and after I started taking the medication my doctor phoned me to say I had to go on B12 and it got put on my repeat prescription list. I hope you get everything sort soon. Take care x

  • Thank you. I will discuss with my doctor.

  • I also have B12 deficiency, and have monthly injections.

    If you look up b12 deficiency it makes for an interesting read.

    I also know when my levels are depleting !

  • Thank you. I really think I need B12 supplements as I really do feel dizzy and faint. Worse today and my tonge is still sore.

    Thanks for your reply

  • No worries, hope you get sorted soon, the injections do make a difference, they feel like the elixir of life to me x.

You may also like...