Weekly split-dose regimen for oral methotrexate reduced polyglutamation in red blood cells in patients with rheumatoid arthritis compared with single-dose regimen: Results from a multicentered randomized control trial

Aims: We compared the incidence of adverse events between single and divided-dose regimens of methotrexate (MTX) by using a multicenter randomized controlled trial.

Methods: Eighty-nine patients with insufficient control on MTX 8 mg/wk were randomly assigned into single-dose (39 patients) or triple dose (39 patients) groups. The MTX dose for all patients was gradually increased to 16 mg/wk. The primary endpoint was the occurrence of liver dysfunction during the observation period (20 weeks).

Results: There were no differences in baseline data and MTX dose at Week 20 between groups. There was no significant difference in the incidence of liver dysfunction between groups (single dose, 3 [7.7%] patients vs. triple dose, 5 [13.2%] patients; P = .455). The incidence of adverse event increased in triple dose (single dose, 12 [30.8%] patients vs. triple dose, 20 [51.3%]), but the difference was not significant (P = .066). There was no significant difference in disease activity between groups, although MTX-triglutamate (PG3), MTX-PG4, and MTX-PG5 were significantly higher in the single dose group.

Conclusions: Weekly split dosing reduced the polyglutamation of MTX. There was no significant difference in efficacy and safety between the 2 groups.

Keywords: methotrexate; polyglutamate; rheumatoid arthritis.