Patients with rheumatoid arthritis treated with methotrexate (MTX): concentrations of steady-state erythrocyte MTX correlate to plasma concentrations and clinical efficacy.

Abstract

Our results indicate that clinical efficacy and Ery-MTX may have a causal relation and that measurement of Ery-MTX or estimation of AUC in a software model provides useful guidelines to the clinician when starting MTX therapy in patients with RA. The latter can be performed immediately after initiation of therapy.