Eczema Medication Series – Methotrexate

This is a series on some of the medication that I’ve collated from parents who shared in forums. My baby with eczema hadn’t been prescribed these, but my usual investigative self got interested after reading mixed feedback on these medicines. Do share in the comments your child’s experience, and the effect on his/her eczema.

What is Methotrexate?
Methotrexate is an antimetabolite which slows down the metabolism of new cells (for instance prescribed to reduce growth of cancer cells). It works via inhibiting dihydrofolate reductase (DHFRase), an enzyme involved in the synthesis of DNA, RNA. It may be prescribed for advanced stages of cancer, severe active rheumatoid arthritis and certain types of cancers. It is also used to treat skin conditions – severe psoriasis, whereby methotrexate decreases the formation of skin cells to prevent the formation of scales. It may also be prescribed for those with severe eczema whose treatment using cyclosporine or corticosteroids are discontinued, as methotrexate has anti-inflammatory properties. Methotrexate also lowers the activity of the immune system.

It can be taken orally or by injection, and patient needs to follow the prescription carefully, especially the dosage or frequency (may be weekly for treatment of skin condition). The dosage prescribed will be determined by the doctor, usually for skin-related, it will be a low dosage, and dosage may vary during the course. It is important to follow-through with the prescription, and not terminate it once you self-assessed your condition has improved.

Monitoring
Certain tests may be requested by your doctor, to assess the side effects of methotrexate, such as blood and liver tests.

Warning
Check with your doctor how much fluid you need to be taking during the course as drinking more water can help to reduce toxicity in kidneys. If you are on non-steroidal anti-inflammatory medication such as aspirin, ibuprofen, choline magnesium or magnesium salicylate, do check with the doctor the safety of these medications as they can increase the level of methotrexate in the blood. Also check on medication such as acitretin, azathioprine, isotretinoin, sulfasalazine or tretinoin that may increase concentration of methotrexate in the blood or increase toxicity for certain body organs – liver, kidney and bone marrow (better to tell the doctor of drugs, medicines, supplements and vitamins you are taking). There is associated risk with liver damage, so do check on alcohol consumption.

There may also be sensitivity to light, so take sun protection measures and avoid sunlight. Do not drive as a possible side effect is dizziness. Avoid contact with people who are ill, and also those who have taken a recent nasal flu vaccine or who has chickenpox (also check with the doctor before getting vaccinated) as methotrexate has mild immune suppressive effect. Also check on what sports you can engage in, to prevent cuts or injury. Wash your hands also to prevent infection.

Side Effects
Watch for side effects, and let your doctor know; some of the side effects are:
Chills, fever, rash, peeling skin, headache, mouth sores, vomiting, diarrhea, nausea, loss of appetite, hair loss, swollen gums, red eyes, sore throat, bleeding, bruising, paleness, difficulty breathing, excessive fatigue, yellowing of skin or eyes, seizures, fainting, difficulty with body movements, vision changes and painful urination.
Symptoms such as diarrhea, black, tarry or bloody stools or bloody vomits may be related to damage to the lining of intestine due to Methotrexate. Do call your doctor immediately. Also, if you had stomach ulcers or previous medical conditions related to intestines, do inform your doctor.
Refer here for which side effects are more common, and which are less.

Diet
Folic acid may be prescribed as a supplement during the course, but this depends on your doctor as studies are not definitive in this area. Folic acid may in some ways reduce the effectiveness of methotrexate, thus may be prescribed on days when patient need not take methotrexate.

Most Importantly, Does it Work?
I’ve found a few studies online, and the various conclusions are:
1. In this study of 60 patients, methotrexate found to improve mild to moderate eczema
2. In a study of 42 patients, both methotrexate and azathioprine showed clinical improvement in eczema for adult patients in the short term.
3. In a study of 25 patients with paediatric discoid eczema, about 19 children showed improvement after 10.5 months.
4. In this study of 20 patients, methotrexate found to be effective, but there were also patients who dropped out from the study due to side effects.

A point to note is above studies were small sample sizes (and I’ve found a few others of even smaller sizes), possibly due to methotrexate prescribed only for severe instances, which had not responded to corticosteroids or cyclosporine. Do share your experience in the comments!