What is the recommended dosage of folic acid to take with a methotrexate (MTX) prescription of 25 milligrams per week?

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Last updated: February 25, 2025View editorial policy

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From the Guidelines

When taking methotrexate 25mg weekly, you should take at least 5mg of folic acid per week to minimize side effects and maximize the therapeutic benefits of methotrexate therapy. This recommendation is based on the strongest evidence available, which suggests that folic acid supplementation reduces gastrointestinal and liver toxicity of methotrexate without reducing its efficacy 1. The exact timing and dosage of folic acid may vary depending on individual patient needs and response to methotrexate, but a minimum of 5mg per week is strongly recommended.

Some key points to consider when taking folic acid with methotrexate include:

  • Folic acid supplementation can help reduce side effects such as nausea, mouth sores, liver problems, and blood cell abnormalities
  • Methotrexate works by inhibiting folate metabolism, which can deplete the body's folate stores and lead to these unwanted effects
  • Folic acid replenishes these stores without interfering with methotrexate's therapeutic benefits for conditions like rheumatoid arthritis, psoriasis, or certain inflammatory conditions
  • The recommended dosage of folic acid may be adjusted based on individual patient response to methotrexate and any side effects experienced

It is essential to follow a doctor's specific instructions regarding folic acid dosing, as they may adjust the recommendation based on individual patient needs. However, the minimum recommended dosage of 5mg per week should not be exceeded without consulting a healthcare professional. According to the evidence, prescription of at least 5mg folic acid per week with methotrexate therapy is strongly recommended 1.

From the Research

Folic Acid Dosage with Methotrexate

The recommended dosage of folic acid to take with a methotrexate (MTX) prescription of 25 milligrams per week is:

  • 5-10 mg per week, as suggested by 2
  • 10 mg per week, as compared to 30 mg per week in 3, which found no additional benefit of the higher dose Some studies suggest that folic acid supplementation can help reduce methotrexate toxicity and side effects, such as:
  • Nausea, stomatitis, and hepatotoxicity, as mentioned in 4
  • Undesirable symptoms and laboratory abnormalities, as discussed in 3

Key Considerations

When taking folic acid with methotrexate, consider the following:

  • Folic acid should be taken daily or weekly, depending on the specific regimen, as discussed in 5 and 4
  • The dose of folic acid may vary depending on the individual patient and their specific needs, as suggested by 3 and 2
  • Folic acid supplementation can help prevent folate deficiency and hyperhomocysteinemia, which may be associated with cardiovascular disease, as mentioned in 2

Methotrexate Dosage and Administration

Methotrexate dosage and administration may vary depending on the individual patient and their specific condition, as discussed in:

  • 6, which recommends an initial dose of 10 mg/week, with rapid dose escalation to 15-20 or 25 mg/week as needed
  • 3, which used a dose of 10 mg/week, escalating to 25 mg/week by 12 weeks

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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