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British Lung Foundation
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Lung problems, methotrexate and folic acid

I just read that use of folic acid with methotrexate etc can increase risk of lung cancer? Is this true? I was given folic acid when I was prescribed methotrexate but this information has really scared me ... do I have to take the folic acid?

I was also told that methotrexate can actually increase inflammation in the lungs so why are docs giving me this when I already have inflammation in my lungs that needs reducing not increasing !!! I'm so confused!!

10 Replies


Found article which contradicts.

Quote from.

Methotrexate (MTX) was introduced in 1947. Because it slows down the growth of rapidly dividing cells it was used in high doses to treat people with leukaemia and other forms of cancer. In the early 1950s it was used in much lower doses to treat people with the skin condition psoriasis. Some people who had an inflammatory arthritis associated with their psoriasis noted that their joints improved as well as their skin, as did a few people with rheumatoid arthritis (RA) who were given MTX.

Folic acid is taken to counteract the side effects of Methotrexare.

Full article


The concerns for Folic Acid are in high dosage,


Cancer: Early research suggests that taking 800-1000 mcg of folic acid daily might increase the risk of cancer. Until more is known, people with a history of cancer should avoid high doses of folic acid.

Full article



Thankyou so much for taking the time to respond ..its been helpful for me xxx ill have to take the folic acid I expect ..!


Hi Defo is confusing but do have to take as your body is producing lots of cells but the quantity is lacking quality SO i assume mtx is to slow cell growth and folic acid is to give cells the quality the need to help with your lung disease.

Its all confusing but i guess you might have stomach pain give high cell turn over.

Am sure docs going to follow up test BUT like you i use to read up on meds and give myself the willies.

So i try not to take advice literally as most time the just covering the #%%% so list anything and everything that could or might happen

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LOL! ! Yes the damn research does often give me the wiles! You cheered me up mate! O think will have to be a good girl and take the folic ACID ..I'm already a nut case!😚

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Hi Minsha,

I take the various medications for COPD whilst (for the last six years) I also take low dose Methotrexate (10mg/week) & folic acid. Being a bloke I therefore know better than any doctor so decided the folic acid wasn't necessary! At my next appointment (five months later) they listed all the side effects of taking methotrexate without folic acid ... mood swings, depression, headaches etc, etc (quite a long list - mainly mental health) and I ticked every single box!!!

So, although I obviously can't admit that I was wrong, I take my folic acid like a good boy! Over the six years my lung capacity has INCREASED slightly but this is probably due to stopping smoking only a short while before the first lung function test.

Methotrexate is a powerful drug (hence only prescribed for once a week dose) and not something I'm willing to "mess with" - I can only say that I've never had any issues, not read any credible reports about issues and always treat it with extreme care.

Hope my experience helps give you some answers. I can't say you should/shouldn't take the folic acid - take it over with your clinician if you have concerns - mine is really good, loads of experience and very approachable - hope yours is the same.

Good luck.


Thank you so much for this reassuringg response ..it really helps me to think things through x


Methotrexate tends to reduce the amount of folate in your system. Folate is a very important vitamin and also helps to minimise the less pleasant side effects of methotrexate.

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Thanks care x


Hi it is really up to you if you take this medication. As I said I was offered methotrexate. And refused to take it as one of the side effects were damage to the lungs I would of had to take folic acid too. This was for psoriatic arthritis and psoriasis. I have never been offered it for my COPD. But I do take two other DMARD for my arthritis.


Thanks not to bad x


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