CGP-28014 is a catechol-O-methyltransferase inhibitor potentially for the treatment of Parkinson's disease.Although CGP-28014 increases the renal excretion of both dopamine and dihydroxyphenylacetic acid (DOPAC) it does not affect renal sodium handling indicating a different mechanism of action. CGP-28014 significantly reduced the levels of homovanillic acid (HVA), but did not modify DA and 3,4-dihydroxyphenylacetic acid (DOPAC).