Methotrexate

Methotrexate

Methotrexate is a disease-modifying antirheumatic drug (DMARD) commonly prescribed for autoimmune diseases such as rheumatoid arthritis, Crohn's disease, ulcerative colitis, psoriasis, juvenile idiopathic arthritis, and autoimmune neurological disorders. It works by modifying certain immune cells, suppressing the immune system, and decreasing inflammation, which can lead to less painful, swollen joints and reduced disease activity. There are no medications that are U.S. Food and Drug Administration approved for retroperitoneal fibrosis but methotrexate has been used to help with control of the disease and reduce the need for prednisone.

How Methotrexate is Taken

Methotrexate can be taken orally as pills or given by subcutaneous injection. The oral dose is usually taken all at once, or in some circumstances it may be split into two taken over a 24-hour period (for example if the dose is 6 tablets once weekly – 3 tablets could be taken in the morning and 3 tablets in the evening). Injections may be recommended for those who don't respond to oral methotrexate or experience stomach upset. Methotrexate is typically taken once a week.

Before Starting Methotrexate 

It is crucial to inform your healthcare provider about:

• All other medicines you take, including prescription, over-the-counter drugs, dietary or herbal supplements, and vitamins.

• Any medicine allergies you have.

• Existing medical problems such as kidney, liver, or lung disease.

• Your vaccination history and any infections you currently have or recently had.

Important Considerations During Treatment

Folic Acid Supplementation

Methotrexate changes how the body uses folic acid. To minimize toxicity and side effects like oral ulcers, nausea, and anemia, folic acid (1 mg daily or 5 mg weekly) is often prescribed to be taken with methotrexate, usually 12 to 24 hours after the methotrexate dose.

Monitoring

Regular follow-up appointments and testing are essential. This includes blood tests to check kidney, liver, and blood counts (hemoglobin, white blood cell count), typically done monthly for the first three months and then every three to four months thereafter].

Vaccinations

People taking methotrexate are at an increased risk of infections. Non-live (inactivated) vaccines are generally safe, but live (attenuated) vaccines should be avoided while on methotrexate, and potentially for a period before starting and after stopping the medicine. When receiving a vaccine, it is sometimes suggested to hold the dose on the week following the vaccine administration to increase the response to the vaccine.

Alcohol

Alcohol should be limited and if possible avoided while taking methotrexate due to the risk of liver toxicity.

Sun Exposure

Limit exposure to ultraviolet light and use appropriate sun protection, as methotrexate can cause photosensitivity in some patients.

Response Time

Most people start to see benefits from methotrexate within three to six weeks, though it may take longer in some circumstances.

Potential Side Effects 

While many people tolerate methotrexate with few side effects, some can occur.

Common Side Effects

Flu-like symptoms (cough, nausea, vomiting, diarrhea, headache, fatigue), dizziness, mouth sores, elevated liver enzymes, and injection site irritation (for subcutaneous administration). Gastrointestinal symptoms like nausea, vomiting, abdominal pain, and poor appetite are experienced by 20% to 70% of patients.

Serious Side Effects

Liver Toxicity: This is a common potential side effect, and monitoring liver function tests is crucial. Patients with psoriasis, diabetes, obesity, hepatic steatosis (fatty liver) may have a higher risk.

Bone Marrow Suppression: Methotrexate can cause a lowered blood cell count, including leukopenia (low white count), anemia (low hemoglobin), and thrombocytopenia (low platelets). This is usually dose-dependent and can be managed with folic acid.

Lung Problems: Acute pneumonitis (irritation of the lungs) or pulmonary fibrosis can rarely occur. Pulmonary symptoms like a dry, nonproductive cough may require stopping treatment. Smokers are at increased risk of lung issues.

Infections: Methotrexate can increase the risk of infections, including opportunistic (less common) infections.

Malignancy: There is an increased risk of certain cancers, such as skin cancer and lymphoma. Lymphomas may sometimes regress after stopping methotrexate.

Kidney Problems: Methotrexate is cleared by the kidneys, so kidney function should be monitored. A decrease in kidney function may require a dose reduction.

Pregnancy and Breastfeeding 

• Methotrexate is teratogenic, meaning it can harm a fetus and cause fetal death or congenital anomalies.

• Do not take methotrexate if you are pregnant or if there is a chance you may become pregnant.

• Women of reproductive potential should use two forms of birth control while taking methotrexate and for at least 3 to 6 months after the last dose.

• Methotrexate may affect men's sperm quality. Men should use contraception and wait at least 3 months after stopping methotrexate before trying to conceive.

• Do not breastfeed while taking methotrexate.

When to Contact Your Care Team 

Contact your care team immediately if you experience:

• Signs of infection (fever of 100.4°F/38°C or greater, flu-like symptoms).

• Symptoms of liver problems (upset stomach, loss of appetite, nausea, vomiting, pale stool, dark urine, yellow skin/eyes, easy bruising or bleeding).

• Symptoms of kidney problems (trouble passing urine, swelling in legs, ankles, or feet).

• Skin problems (sores, blistering, peeling, or discoloration).

• Symptoms of low blood cell counts (increased fatigue, weakness, dizziness, headache, trouble breathing).

• Trouble breathing or symptoms of a serious allergic reaction (swelling of lips, tongue, throat, face, or eyelids; shortness of breath, wheezing, chest tightness, dizziness, lightheadedness, rash, hives, itching).

• Your symptoms do not improve or worsen, or you develop new symptoms.

• You are prescribed a new medicine.

• You think you may be pregnant or plan to become pregnant or breastfeed.

This information is not a substitute for professional medical advice. Always discuss your specific situation with your healthcare provider.