A 30-year-old female with lupus nephritis is started on methotrexate for adjunctive therapy. She is also prescribed folic acid supplementation. The primary reason folic acid is given alongside methotrexate in non-oncologic uses is to:

• A Enhance the antiproliferative effect of methotrexate on synovial cells
• B Reduce methotrexate-related mucositis and hepatotoxicity without abrogating efficacy ✓
• C Rescue bone marrow cells from methotrexate toxicity acutely
• D Prevent precipitation of methotrexate in renal tubules

Explanation

In non-oncologic uses such as rheumatoid arthritis and lupus, low-dose folic acid (1–5 mg/day) co-administration reduces the incidence of methotrexate adverse effects including mucositis, hepatotoxicity, and nausea without significantly impairing its therapeutic anti-inflammatory efficacy. Folinic acid (leucovorin) is the agent used for acute 'rescue' in high-dose oncologic regimens. The anti-inflammatory mechanism of low-dose methotrexate operates partly through adenosine pathway rather than pure folate antagonism.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.