Erythrocyte Membrane Gold Levels After Treatment with Auranofin and Sodium Aurothiomalate

Abstract

Triethylphosphine gold-2,3,4,6-tetra-o-acetyl-l-thio-d-glucopyranoside (auranofin and sodium aurothiomalate; Myocrisin®) are two chemically different gold compounds used to treat rheumatoid arthritis. This study highlights the interaction, in vivo, of these drugs with erythrocyte membrane in patients with rheumatoid arthritis. Fifty-eight patients with definite or classical rheumatoid arthritis were included in this study and randomly allocated to three groups as 18 patients in the Myocrisin® group, 20 patients in the auranofin group, and 20 patients in the placebo group. The drugs appeared to react, in vivo, in different ways. With Myocrisin®, the level of gold in erythrocyte membrane was, initially, very high and decayed exponentially afterwards, whereas auranofin produced a constant high level up to 36 weeks. The erythrocyte membrane gold level in nonsmokers was higher than that in smokers in the auranofin group, and it decreased with an increase in the number of cigarettes smoked (r = 0.836 P < 0.01); no such correlation was observed in the Myocrisin® group. In a changeover study, auranofin appeared to change the nature of erythrocyte membrane after reacting with it and rendering it incapable of picking up any gold from Myocrisin®. In the case of auranofin, the hemolysate membrane gold level was found to correlate with clinical improvement.