Revamilast is an orally active, potent and selective phosphodiesterase 4 (PDE 4) inhibitor that is being studied for its potential in treatment of inflammatory disorders. PDE 4 inhibitors attenuate the inflammatory response and suppress many cytokines, including TNF-α production in mononuclear cells. Initial studies showed no serious adverse events in healthy volunteers and phase II studies have evaluated the effect of revamilast on long function and rheumatoid arthritis.