Similar effect of co-administration of methotrexate and folic acid for the treatment of arthritis compared to separate administration.

ABSTRACT

OBJECTIVES: MTX is the recommended first-line treatment for RA associated with folic acid (FA) to reduce side effects related to MTX. Here, we proposed to test a co-administration of MTX with FA in the rat adjuvant-induced arthritis (AIA) on efficacy. MATERIAL AND METHODS: AIA was induced in female Lewis rats and treated with MTX in three groups. The first group of rats received only MTX (n = 13), whereas the second received MTX and FA on the same day (n = 14). The third group received FA one day after MTX (n = 14). Arthritic index (AI), ankle circumference (AC), ankle microcomputed tomography, and blood tests assessed arthritis severity and MTX tolerance. RESULTS: AI and AC were similar in MTX groups at various time points. Bone erosion and bone loss parameters were similar in all groups. MTX-PG1 was found at similar levels in various MTX groups and correlated negatively with arthritis severity. Finally, haematology and metabolic parameters were found at a similar level in MTX groups. CONCLUSION: Co-administration of MTX with FA on the same day did not reduce efficacy compared with FA application one day after MTX. Thus, co-administration of MTX and FA could be more convenient and improve compliance in patients.