Methotrexate is a drug used to induce and maintain remission of Crohn’s disease in patients who are intolerant of mercaptopurine.
It appears to work best when given by an injection under the skin or into the muscle each week. It may be taken as tablets but it may be less effective. The starting dose is 25mg/wk which is decreased to 15mg/wk after first 16 weeks. To reduce the risk of side effects from methotrexate, I recommend you take a vitamin called folic acid once a week, but you should NOT take this on the same day as the methotrexate treatment but ideally the day before and after it (“folate sandwich”).
Methotrexate suppresses your immune response and reduces inflammation.
The benefits of methotrexate treatment may not be evident for 4-8 weeks.
Patients who respond to methotrexate usually remain on it for many months and perhaps several years as long as the blood test monitoring remains satisfactory.
Fortunately many patients do not suffer any side effects with this treatment. Nausea or vomiting is the commonest side effect likely to occur. Other common side effects include: mouth ulcers; diarrhoea; fatigue; symptoms of a cold/flu like illness; joint pain; insomnia; facial flushing; eye irritation; dizziness; mild hair loss; loss of libido/impotence; decreased fertility (reversible on completion of treatment).
Other rare side effects include: headache; acne; skin irritation and itching; increased sensitivity to light; tingling / numbness; dry cough and/or shortness of breath.
Should you develop any of these troublesome symptoms please let me know.
You will need to have blood tests taken at regular intervals throughout administration of methotrexate to check that the drug is not damaging your bone marrow or liver. If the blood tests become abnormal, I will advise you to stop the drug and normally, the test results return to normal.
In addition: do not receive any live vaccines (rubella, polio); avoid contact with people who have infections.
Do not become pregnant whilst taking methotrexate treatment. Methotrexate may damage sperm and so birth control is essential for both men and women. Contraception (for both sexes) should be continued for at least 3 months after stopping methotrexate treatment.