Methotrexate is a medication prescribed to manage Crohn’s disease, a long-term inflammatory condition affecting the digestive system. This article explains how methotrexate helps control symptoms, its administration, timeline for effectiveness, common side effects, and safety considerations.
Understanding Crohn’s Disease
Crohn’s disease is a chronic condition characterized by inflammation within the digestive tract. This inflammation can occur anywhere from the mouth to the anus, though it most commonly affects the small intestine and the beginning of the large intestine. The disease is a type of inflammatory bowel disease (IBD), where the body’s immune system mistakenly attacks healthy tissues in the digestive tract. This ongoing inflammation can lead to a range of symptoms, including abdominal pain, diarrhea, fatigue, and weight loss.
The chronic nature of Crohn’s disease means that symptoms can come and go, with periods of active disease (flare-ups) and periods of remission, where symptoms are minimal or absent. Over time, persistent inflammation can lead to complications such as intestinal blockages, fistulas (abnormal connections between parts of the intestine or other organs), and abscesses (pus-filled pockets). While there is currently no cure for Crohn’s disease, treatments aim to reduce inflammation, manage symptoms, and achieve long-term remission.
How Methotrexate Helps Crohn’s
Methotrexate is a medication used to treat moderate to severe Crohn’s disease, especially when other treatments like azathioprine or multiple courses of steroids have not been sufficient. It functions as an immunomodulator, meaning it works by dampening the overactive immune system to reduce the inflammation in the bowel.
The medication achieves its effects by interfering with the body’s use of folic acid, a vitamin necessary for cell growth and function. At the low doses used for Crohn’s disease, methotrexate inhibits cellular proliferation, decreases the formation of antibodies, and reduces the production of inflammatory mediators like interleukins. This overall reduction in immune system activity helps to prevent flares and can reduce the need for corticosteroids. Methotrexate can also be used in combination with other IBD medications, such as anti-TNF treatments like infliximab or adalimumab, to improve overall effectiveness and potentially reduce the body’s tendency to produce antibodies against these biologic drugs.
Administering Methotrexate and Its Timeline
Methotrexate is taken once a week, and it is available in two main forms: tablets or injections. Oral tablets are taken by mouth, often after food, and should not be crushed or chewed. Injections can be given either subcutaneously (under the skin) or intramuscularly (into the muscle), commonly in the abdomen or thigh. Many healthcare providers prefer injections as they are often more effective and may cause fewer side effects compared to tablets.
Regardless of the administration method, methotrexate is a slow-acting medication. It can take 1 to 3 months before patients start to experience its benefits, with full effects sometimes taking longer. Because of its gradual onset, methotrexate is not used for treating short-term flare-ups but rather for achieving and maintaining long-term remission. It is crucial to adhere to the once-weekly dosing schedule; taking methotrexate daily can be dangerous.
Managing Side Effects and Safety Monitoring
Methotrexate can cause side effects, though many people tolerate it well. Common side effects include nausea, vomiting, diarrhea, fatigue, and mouth ulcers. Some individuals may also experience headaches, a general feeling of fogginess, or increased skin sensitivity to the sun. Taking the medication with food or in the evening may help reduce some gastrointestinal side effects, and injected methotrexate often causes less nausea than oral tablets.
To counteract some of these side effects, particularly nausea and bone marrow suppression, folic acid supplementation is routinely prescribed alongside methotrexate. Folic acid, a form of vitamin B9, helps the body cope with methotrexate’s effects by reducing gastrointestinal and liver toxicity. It is taken once a week, not on the same day as methotrexate, or sometimes daily, depending on the prescribed regimen.
Regular blood tests are required during methotrexate treatment to monitor for complications. These tests check for abnormalities in blood counts, as methotrexate can suppress bone marrow function, and monitor liver and kidney function due to toxicity. Initially, blood tests may be required every two weeks for the first three months, then less frequently, such as every three to four months, once the dose is stable and well-tolerated. This close monitoring allows healthcare providers to detect and address any issues promptly. Patients should contact their healthcare team if they develop signs of infection, such as fever, or experience breathing difficulties or a dry cough, as these could indicate more serious, though less common, side effects like lung inflammation.
Important Considerations for Methotrexate Use
A primary consideration for methotrexate use involves pregnancy. Methotrexate can increase the risk of spontaneous abortion and birth defects. Therefore, women of childbearing age taking methotrexate must use reliable contraception. Women planning a pregnancy should discontinue methotrexate at least three to six months before attempting conception.
Men should also use reliable contraception and stop the medication for at least three months before attempting to father a pregnancy. Methotrexate should not be used by breastfeeding mothers. Another common misconception is that methotrexate, at the doses used for Crohn’s disease, is equivalent to chemotherapy for cancer. While methotrexate is used in much higher doses to treat certain cancers, the significantly lower doses prescribed for Crohn’s disease work differently by modulating the immune system to reduce inflammation, and the risks of side effects are not as high as with cancer chemotherapy.