Effect of the new selective COMT inhibitor CGP 28014 A on the formation of 3-O-methyldopa (3OMD) in plasma of healthy subjects.

CGP 28014 A is a specific inhibitor of catechol-O-methyl transferase (COMT). The effect on COMT was assessed with the levodopa test in 5 unmedicated subjects and after pretreatment with 200-600 mg CGP 28014 p.o. Plasma concentrations of DOPA, 3-O-methyldopa (3OMD), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid were measured. CGP 28014 A decreased 3OMD not dose-related by 67% (p less than 0.05). This, and an increase of DOPAC shows COMT inhibition by this compound in humans.