Changes in plasma homocysteine in arthritis patients starting treatment with low-dose methotrexate subsequently supplemented with folic acid

In 15 patients with rheumatoid arthritis (RA) (n = 13) or psoriatic arthrit is (PsA) (n = 2) p-homocysteine and erythrocyte folate (erc-FA) were measur ed before start of methotrexate (MTX) treatment, after 4 weeks of MTX treat ment (median 10mg per week), and after further 4 weeks of treatment with MT X (median 12.5 mg per week) supplemented with folic, acid (FA) (15 mg per w eek). Mean p-homocysteine were 12.3 +/- 3.4 mu mol/l, 14.6 +/- 5.8 pmol/l ( p < 0.05) and 10.3 +/- 3.0 mu mol/l (p < 0.01) respectively. P-homocysteine concentrations were negative correlated to ere-FA after 4 weeks (rho -0.58 ; p < 0.05). It is concluded that treatment with MTX induces a significant rise in p-homocysteine that is neutralised by FA supplementation. Supplemen tation with FA from the start of MTX treatment is recommended considering t he increased risk of cardiovascular disease that is associated with elevate d concentrations of p-homocysteine.