Clozic is a potential anti-arthritic agent. Concentrations of Clozic greater than 50 μM cause a dose-dependent decrease in the amount of matrix protein synthesized by RHMC cell cultures. Inhibition of RHMC cell culture growth by Clozic occurs in a dose-dependent manner. The anti-proliferative effect of Clozic on RHMC cell growth is reversible. Lactate dehydrogenase (LDH) levels in media taken from RHMC cell cultures exposed to 500 μM Clozic for 3 days do not significantly differ from LDH levels in control cell culture media.