IRCT20170716035126N1 IRCT 2017-12-22 Ardabil University of Medical Sciences Evaluating the efficacy of methotrexate in pain severity reduction and improvement of quality of life in patients with moderate to severe knee osteoarthritis Evaluating the efficacy of methotrexate in pain severity reduction and improvement of quality of life in patients with moderate to severe knee osteoarthritis 2017-12-22 anticipated 100 Complete https://irct.ir/trial/26638 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: Patients will be randomized into two groups using random number blocks and using sealed envelopes, Blinding description: Patients and the person evaluating the treatment outcome will be blinded to the allocated groups. N/A Knee osthoarthritis. Intervention 1: Both groups will be administered glucoseamine sulfate 1500 mg daily and then in intervention group, methotrexate with the dose of 7.5 mg (3 pills) weekly will be administered and then increased to 15 mg weekly. Intervention 2: both groups will be administered glucoseamine sulfate 1500 mg daily and in placebo group, placebo will be administered 3 pills weekly. Undecided - It is not yet known if there will be a plan to make this available