BACKGROUND AND OBJECTIVE: Due to low effectiveness of drugs in osteoarthritis treatment, finding new drugs always consider. Although colchicine has been described as a disease moderator medicine for osteoarthritis disease or symptoms, few studies have been carried out about the effect of it in soothing symptoms of patients with knee osteoarthritis.

METHODS: This RCT was conducted on 62 patients with idiopathic knee osteoarthritis. Pain intensity, the degree of functional disability, and the patients’ clinical health were assessed by VAS, modified WOMAC index and modified HAQ questionnaire, respectively. The patients were then randomly assigned to two groups of oral colchicine group (0.5mg/bid) and placebo group and undergone treatment for 4 months. Assessment repeated in 3^rd and 4^th months. IRCT code: IRCT2015071623240N1.

FINDINGS: Compared to the beginning of the study, the intensity of pain in both groups was reduced and the degree of functional disability and the patients’ clinical health were improved in the 3^rd and 4^th months of study, too. Nevertheless, the percentages of pain severity improvement in colchicine group in comparison to placebo were significantly higher (3^rd mo: 29% vs. 16%, respectively, p=0.030; 4^th mo: 37% vs. 20%, respectively, p=0.014). In addition, the percentages of physical function improvement in colchicine group in comparison to placebo were significantly higher (3^rd mo: 26% vs. 16%, respectively, p=0.048; 4^th mo: 28% vs. 20%, respectively, p=0.036).

CONCLUSION: Use of colchicine for four months in patients with knee osteoarthritis can reduce pain and improve physical function.