Severity of methotrexate side effects (mucositis)

• Mucositis, a side effect of methotrexate (MTX), causes inflammation and ulcers in the oral and gastrointestinal mucosa.is a symptom
• Type A mutation in DNA region rs1128503Research has found that people with this condition tend to have a higher risk of developing severe mucositis.
• The prevalence of type AA in Japanese people is36.1％, approximately twice as high as the world average (17.8%)

Overview Methotrexate is a drug used to treat a variety of illnesses. Although it was first developed to treat cancer, it is now widely used to treat autoimmune diseases and rheumatoid arthritis. This drug has the effect of suppressing cell division and suppresses the growth of cancer cells. It also has the effect of suppressing excessive immune reactions against autoimmune diseases. Although it is an effective treatment, it has side effects mainly on the digestive system, liver, and blood. Gastrointestinal side effects include mucocytosis (painful inflammation and ulceration of the mucous membrane lining the gastrointestinal tract), nausea, vomiting, diarrhea, and stomatitis. It also has an effect on the liver, and long-term use or high doses may cause liver dysfunction. Blood side effects include anemia and decreased white blood cell counts, making you more susceptible to infections. While methotrexate is a highly effective treatment, if you experience any side effects, it is important to consult your doctor immediately. A study by Gong et al. from Huazhong University of Science and Technology revealed that the side effects of methotrexate are associated with a DNA region called rs1128503. There are three genotypes in this DNA region: AA, AG, and GG, and it was found that people with the A genotype tend to have a higher risk of side effects from methotrexate.

Methotrexate (MTX) is an anti-metabolite drug widely used in cancer treatment, rheumatoid arthritis, and autoimmune diseases, and can cause mucositis as a side effect.Mucositis is a condition in which painful inflammation and ulcers develop in the mucous membranes that line the gastrointestinal tract.

Mechanism of action of methotrexate

Methotrexate is a drug that has two actions:

• Cell division inhibitory effect:Inhibits cancer cell proliferation and suppresses tumor growth
• Immunosuppressive effect:Suppressing excessive immune responses in autoimmune diseases

Classification of main side effects of methotrexate

What are the symptoms of mucositis?

Mucositis is inflammation and ulceration that occurs in the mucous membranes that line the digestive tract (from the oral cavity to the intestinal tract).The following symptoms are characteristic.

• Pain, swelling, and redness in the oral cavity
• Dysphagia (difficulty swallowing)
• Ulceration of the gastrointestinal tract
• Difficulty getting nutrition

What to do if side effects occur

While methotrexate has a high therapeutic effect, if side effects occur,Consult your doctor immediatelyis important. Dose adjustment or switching to an alternative drug may be considered.

Relationship between DNA region rs1128503 and mucositis risk

A study by Gong et al. (2021) from Huazhong University of Science and Technology found that the DNA region rs1128503 was associated with the severity of methotrexate side effects (mucositis).

• There are three genotypes of rs1128503: AA, AG, and GG.
• Genotype with type A mutation(AA type/AG type) people tend to have a higher risk of severe mucositis.

Genotype distribution comparison between Japanese and the world (rs1128503)

Q1. What are the side effects (mucositis) of methotrexate?

Methotrexate (MTX) is an anti-metabolite drug used in cancer treatment and rheumatoid arthritis.Mucositis may occur as a side effect, causing painful inflammation and ulcers in the mucous membranes of the oral cavity and gastrointestinal tract.

Q2. Are genes related to the severity of mucositis?

According to a study by Gong et al. (2021) from Huazhong University of Science and Technology,DNA region rs1128503 is associated with severity of methotrexate side effect (mucositis)It turns out that it does. People with the type A mutation (AA type/AG type) tend to be at higher risk.

Q3. What are the side effects of methotrexate?

The main side effects aredigestive system(mucositis, nausea, vomiting, diarrhea, stomatitis),liver damage(liver dysfunction during long-term/high-dose use),blood abnormalityIt is classified into three types: (susceptible to infection due to anemia and decreased white blood cells).

Q4. What is the distribution of the rs1128503 genotype in Japanese people?

The genotype distribution of rs1128503 in Japanese people isAA type 36.1%, AG type 47.9%, GG type 15.9%It is. Compared to the world average (AA type 17.8%), the percentage of people with type AA tends to be about twice as high.