*Only about 1% reaches the cerebrospinal fluid space. However, the addition
of a decarboxylase inhibitor increases the availability in the plasma and in the
central nervous system considerably. Dopamine is metabolized by the monoamine-oxidase
(MAO) and the catechol-O-methyltransferase (COMT).
*DI = decarboxylase inhibitor benserazide (in madopar) or carbidopa (in sinemet).
**The initial dose should, in a first step, be raised to a daily maintenance dose of 300 to 400 mg (in 3 to 5 single doses). Only after a waiting period of several weeks should the dose be increased further. Occasionally higher daily doses are given. There may be inferior fluctuation with sustained release preparations.