As others have said, Methotrexate would be one of the last meds to try. There are several side effects. It's often used to treat RA. Here's a copy of what I read on 'Drugs-dot-com':
What is methotrexate?
Methotrexate interferes with the growth of certain cells of the body, especially cells that reproduce quickly, such as cancer cells, bone marrow cells, and skin cells.
Methotrexate is used to treat certain types of cancer of the breast, skin, head and neck, or lung. It is also used to treat severe psoriasis and rheumatoid arthritis.
Methotrexate is usually given after other medications have been tried without successful treatment of symptoms.
Methotrexate may also be used for other purposes not listed in this medication guide.
Important information about methotrexate:
You must use the correct dose of methotrexate for your condition. Methotrexate is usually taken once or twice per week and not every day. Follow the directions on your prescription label. Some people have died after taking this medicine every day by accident. Ask your doctor if you have any questions about your dose of methotrexate or how often to take it.
Methotrexate can cause serious or life-threatening side effects on your liver, lungs, kidneys, and bone marrow (immune system). Do not take this medication in larger amounts, or take it for longer than prescribed. Follow the directions on your prescription label. Do not use methotrexate to treat psoriasis or rheumatoid arthritis if you have liver disease (especially if caused by alcoholism), a blood cell or bone marrow disorder, or if you are breast-feeding a baby. Methotrexate can cause birth defects in an unborn baby. Do not use methotrexate to treat psoriasis or rheumatoid arthritis if you are pregnant. Use an effective form of birth control, whether you are a man or a woman. Tell your doctor if you or your sexual partner become pregnant during treatment.
To be sure methotrexate is not causing harmful effects, your blood will need to be tested on a regular basis. Your kidney or liver function may also need to be tested. Do not miss any scheduled appointments.
There are many other medicines that can interact with methotrexate. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor. Keep a list with you of all the medicines you use and show this list to any doctor or other healthcare provider who treats you.
Before taking methotrexate
Do not use this medication if you are allergic to methotrexate. Do not use methotrexate to treat psoriasis or rheumatoid arthritis if you have:
* liver disease;
* alcoholism or cirrhosis of the liver;
* a blood cell disorder such as anemia (lack of red blood cells) or leukopenia (lack of white blood cells);
* a bone marrow disorder; or
* if you are breast-feeding a baby.
Methotrexate is sometimes used to treat cancer even when patients do have one of the conditions listed above. Your doctor will decide if this treatment is right for you.
If you have any of these other conditions, you may need a dose adjustment or special tests to safely take methotrexate:
* kidney disease;
* liver disease;
* lung disease or pneumonia;
* stomach ulcers;
* any type of infection; or
* if you are receiving radiation treatments.
FDA pregnancy category X. Methotrexate can cause birth defects in an unborn baby. Do not use methotrexate to treat psoriasis or rheumatoid arthritis if you are pregnant. Tell your doctor right away if you become pregnant during treatment.