Methotrexate- primer 1

Methotrexate is used at low doses in conditions like psoriasis, rheumatic diseases, and anti-inflammatory disease. the low dose of methotrexate is 10-25 mg/week. In case of malignancies, methotrexate is given at higher doses above 500mg/week. For further details refer to Conventional DMARDS in Rheumatoid Arthritis, Lecture 4 Clinical use of Methotrexate in Rheumatology

The recommended dose of folic acid supplementation with methotrexate therapy is 5-10 mg/week. Dhir V et al. in their study on ‘Comparison of two different folic acid doses with methotrexate – a randomized controlled trial (FOLVARI Study)’ reported that Higher folic acid doses (>30mg/week) have not been shown to have any additional benefits or drawbacks over low doses (5–10 mg/week).¹

Reference-

1. Dhir V, Sandhu A, Kaur J, Pinto B, Kumar P, Kaur P, et al. Comparison of two different folic acid doses with methotrexate – a randomized controlled trial (FOLVARI Study). Arthritis Research & Therapy [Internet]. 2015 [cited 2022 Nov 3];17(1). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4483203/

Explanation – When methotrexate is taken along with milk, the absorption of methotrexate is reduced, and the action of the methotrexate is affected. For further details refer to Lecture 3 Methotrexate:- Pharmacology, pharmacodynamics, and mechanism

Explanation – The commonly used antidotes used for methotrexate toxicity are leucovorin and glucarpidase. Leucovorin protects healthy cells from toxins that methotrexate’s suppression of decreased folates causes. Glucarpidase acts by removing methotrexate from the body. For further details refer to CS DMARDS in Rheumatoid Arthritis, Safety concern, precautions, and management of adverse events.

Methotrexate is not used for treating renal inflammation due to lupus nephritis, Lung inflammation – ILD due to systemic sclerosis, and Axial inflammation- Spondylarthritis. For further details refer to Conventional DMARDS in Rheumatoid Arthritis, Lecture 4 Clinical use of Methotrexate in Rheumatology