COMT and Parkinson disease: Current treatments of PD include, but are not limited to, levodopa and its combination drug (such as carbidopa); dopamine agonists (such as apomorphine, ropinirole, cabergoline); MAOB inhibitors (such as rasagiline and selegiline); COMT inhibitors (such as entacapone and tolcapone); anticholinergics; anti-inflammatory agents; and vitamins A, E, and C [5,30].