Mouth Sores from taking Methotrexate?

I started taking Methx last February for Sarcoid. Over all I think I have tolerated it quite well. When I first started it, I was sick to my stomach but that ha s pretty much stopped now. I am still tired but that could be from the sarcs.. But lately I have started having sores in my mouth. The whole side of my face was sore and I thought it was from my eye surgery. I went to my retinologist and he said no my eye was fine maybe it was from my tooth. I went to the dentist yesterday and after xrays, he said there was no damage to the nerve or tooth. When it first started, I had three fever blisters on my lower lip. Now I am wondering if it could be the methx. But after this long a period of time I didn't think of this. Has anyone of you had anything list this occur? If so, did you do anything to prevent this? I really hate to go off the methx because it has certainly helped my uvietis. I have been researching it on the web but I am getting a lot of information all at once. Thanks.

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If this is from the methotrexate it is due to low folic acid. You could certainly try taking additional folic acid to try to prevent it - and this is often reccomended to those taking MTX for sarc.

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Hi Pippin,

MTX is well known for causing mouth sores. I took it for 8 weeks. It caused me to bleed so I was taken off it. However, I used to also hate what it did to my mouth. I was taking folic acid anyhow, but it didn't stop the mouth sores. They started the day after I took the MTX on Wednesdays. So Thurs, Fri, Sat it would hurt to eat, and certain things with high acid, salt content couldnt be eaten. I also had to eat soft stuff. I would just start to get better on Sundays, and they would be completely clear by Tuesday and then on Wednesday, they'd be back. It was a regular occurence.


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Those sound like horrible side effects. But as I'm finding out, I have to weigh the side effects to the benefits. At first I was going to ask if you were checked for shingles (it seems like some Sarcoidians are prone to that), but those who have been on methotrexate have had this problem. I haven't been on this med, so I don't know...hope you get to feeling better, take care and always praying, Dawn

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The mouth sores could be from not having enough folic acid. I had them and my doctor told me to take more folic acid - I was taking 1 pill a day and I added 2 more for a total of 3 till the sores went away. She said that the body will get rid of the excess folic acid on its own. I am back to 1 pill a day, but when I get a sore I start taking more folic acid.

I have been taking methotrexate for close to 3 years now and it has been a great help in controling the symptoms of sarcoid. I hope you feel better soon.


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Thanks to all who responded so quickly to my request. My mouth feels a lot better this morning. The dentist gave me the oral rinse, Peridex and I have been doing the biotene four times daily.
I will call my Dr. about increasing the folic acid. Since I will take the methx Monday, I don't want this to start all over. Again thanks. I am so grateful for the help I receive.

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Now I wonder why 3-4 drs didn't check my folic acid when I had mouth sores.

I have found that an organic mouth rinse helped bunches.

Next time I go through a bought of mouth sores I know where to start now. They where not as bad as Pris but sore.

Good luck to ya

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I am on plaquenil and I also just recovered from a very painful mouth sore that caused intense ear pain. (My doctor gave me lidocaine to put on the sore until it healed and it took about 10 days). Do you know if plaquenil can cause this too? What is the relationship between the methotrexate and folic acid levels? Is that true for plaquenil as well?
Any info would be appreciated. I never had such a sore before. I have been on plaquenil for at least 7 months (I have forgotten)

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Hi Hadenuf,

As far as I know plaquenil does not have quite the same effect on the mouth as methotrexate. Methotrexate interferes with the synthesis of folic acid in the body and therefore you need supplementary doses of folate while on it. Methotrexate inhibits synthesis of RNA, DNA and protein and is highly teratogenic. It acts on the T -Cell involved in the disease mechanism.
It is famous for producing mucositis.

Hydroxychloroquine can produce mouth and eye blisters as a side effect. It also works on T-Cells but the actual mechanism of effect in autoimmunes and sarcoid is not fully understood. It is excellent for treating sarcoid hypercalciuria and mild cases of hypercalcemia as it has some effect on macrophage conversion of 1,25D. I took Plaquenil for 7 years without any mouth problems. However, nobody asked me before I went on it about psoriasis. Very mild psoriasis runs in the family, add plaquenil and it makes it into no longer mild psoriasis. I was getting arthritis and nail dystrophies, most of which have now cleared up since stopping it.


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I have never been on Plaquenil so I don't know much about it. I do know that one side effect of methx is mouth sores but I thought because I had been on it almost 2 years and never had one I wasn't going to get them. Someone else will explain the relationship between folic acid and methx better than I can. I only know that the Dr. said I had to take folic acid which I do one per day. Apparently I need more.
I wish I had known about the lidocaine. This was dreadful. It hurt all the way up into my eye and my ear. Because I had just had eye surgery, I was terrified. My retinologist warned me over and over to be careful of getting infected. Methx compromises your immune system and infections are more common with methx users. I thought if was from my eye. The pain lasted about a week or maybe a little longer.
I do not ever want another. Thanks for responding.

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dear pippin been in same situation as you and was put on 5mg folic acid 6 days a week and corsysdyl mouth wash, mouth now cleared up a treat. hope and pray yours clears up soon.

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Dear Pippin

Methotrexate can certainly be the cause of your mouth sores due to not having enough folic acid. I used to take my methotrexate orally 3x weekly. My Rheumatologist switched me to taking it only once a week(by injection) instead and increased me to 2mg daily (except for the day I take my metho) of Folic acid. If this does not help there is a higher potency type of Folinic acid available by prescription taken only once a week (12 hrs after methotrexate Dose) that my Rheumatologist told me about called Leukovorin. you may want to inquire about this!

As for the Peridex....Please be very careful with this med! it know it seems like a harmless mouthwash, but if not taken correctly it will cause massive damage to your teeth. Believe me, I know because I have been there! I had jaw surgery over a year ago and ended up with osteomyelitis/osteonecrosis in my jaw. the surgeon had prescribed me peridex rinse to try to help heal my incision. What he didn't tell me because he apparently did not know is that you should not use peridex unless you have had your teeth professionally cleaned immediatly prior to beginning use of this product! it is to then be used after brushing thoroughly and not before. I have always had good, straight, white teeth, though had to have alot of bonding done due to excessive sensitivity and nerve pain. I have always brushed at least twice daily. Now my teeth are a disaster from Peridex.

This product (since I did not have my teeth professionally cleaned immediately prior to use) adhered to the bonding that I had done all along all of my front teeth. it turned them an awful shade of brown where the bonding was done that now even my dentist cannot remove (and this is after now having 3 professional cleanings since!) It adhered any plaque that had been on my teeth(it will stick to even the smallest amount!) and cemented it to my teeth where the bonding was and sealed it in. It has now begun to decay my teeth where they had been bonded all along the gumlines. I now have to get all of the previous bonding removed and spend several thousand dollars to have all of my dental work redone! Please stop using this product and have your teeth professionally cleaned before you continue to use it. If you begin using a high enough dose of folic acid, you should not need the peridex anymore. The folic acid will work quickly at healing the mouth sores and should also prevent further outbreaks!!!

Hope this helps!!! Good luck!

Be well!


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Dawn, thanks for the warning. I read on the instructions that it might cause discoloration but I had no idea to what extent. Hearing it from someone who has experienced it makes it more meaningful. I am not going to use it anymore. My mouth has cleared up and I will ask my rheumatologist for something safer if it occurs again. I have increased the folic acid. Thanks you and all who responded so quickly.

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Methotrexate interferes with folate to prevent the cells from duplicating, especially rapidly dividing cells like those in your mouth - so by taking folic acid, you give your cells more ingrediants to work with - when I start to get a sore mouth, I take an extra pill or two and I can usually prevent the sores - however, I am also interferring with the ability of the methotrexate to act on the sarcoid when I do this -

When I was on plaquanil, I didn't have mouth sores -

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Hey Karolyn

My Rheumy told me that as long as I wait 12 hrs after my methotrexate dose to take my folic acid, then the folic acid will not cancel out the good effects of the metho, only the bad.

This week, she started me on the leukovorin instead of the folic acid, which is a high level folinic acid concentrate and only needs to be taken once weekly. This, taken 8-12 hrs after my methotrexate injection. The Rheumy says it will not cancel the good benefits of the methotrexate. I guess the problems arise in those who take them too close together or even at the same time.

My original prescribing doc had never prescribed methotrxate before when I first required treatment. I had refused prednisone and told him I would not take it due to the side effects. I told him I would, however take Metho. He told me he needed several days to find out how to prescribe it. Several days later he called me back and told me to split the dose into 3x weekly and to take 1mg folic acid daily. He did not ever inform me that they were not to be taken at the same time as he did not know!!!

I am very glad that i have since switched to my Rheumatologist for my methotrexate management. It is always best to get this kind of medication from someone who has prescribed it before and knows what will interact with it and how! Now I have just had to begin B12 injections weekly as well, and I think I am going to call my Rheumatologist to make sure that this will not interfere with my metho dosing as the pharmacy instructions specifically mention to notify your doc if you take methotrexate. (My PCP already knows, but again, knows nothing about prescribing it!) UGH! I guess it is time to find out if B12 works in the same way as the folic acid.

Be well


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Hello Pippin

Didn't mean to scare you, but rather to suggest a professional cleaning before going any further with it. If the doc had told me that i needed to do this first, I probably would have still had bright pearly whites today instead of being very much embarrassed by my smile!

Just hoping to save some other poor unsuspecting soul the same kind of embarrassment I feel every time I go to smile and remember how awful the stuff has made my teeth look!!! (I settle now for a kind of half smile.) Someday soon I will find the time to have all my dental work redone, however I hate the dentist!!! UGH! Cleanings I can deal with...major overhauls not so good with. I am a big dentist wimp! LOL!

I think they should print it right on the bottle that a professional cleaning is recommended prior to use!!! too many docs don't know if they are not a dentist!!!

Good luck and be well


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