Encapon 200 Mechanism of Action

MECHANISM OF ACTION: Entacapone is a selective and reversible inhibitor of catechol-O-methyltransferase (COMT).
COMT is responsible for catalyzing O-methylation of levodopa to 3-O-methyldopa.
Concurrent administration of COMT inhibitors with levodopa/carbidopa is directed at enhancing levodopa bioavailability (via blockade of 3-O-methyldopa formation), increasing the amount of levodopa brain penetration (by reducing 3-O-methyldopa plasma levels), increasing the elimination half-life of levodopa, and ultimately prolonging and stabilizing its therapeutic effect in Parkinson's disease.
Entacapone provided comparable benefits in Parkinson's disease patients with wearing-off symptoms using either levodopa/benserazide or levodopa/carbidopa.
Pharmacokinetics: Absorption: Systemic: Bioavailability: 35%; food effects: none.
Distribution: Systemic: Vd: 20 L.
Excretion: Systemic: Fecal: 90%; Renal: 10%, 0.2% unchanged.