Based on drug class, the market has been further segmented into Levodopa combination, dopamine agonists, MAO-B Inhibitors, COMT Inhibitors
, and others.
Both were clinical trials with COMT inhibitors
. One of them  used WOQ-9 and reported improvement in most items in proportion of patients with improvements; however, it did not provide data to calculate the effect size.
* Catechol-O-methyltransferase inhibitors (COMT inhibitors
) These are prescribed for people in later stages of Parkinson's disease.
may boost levodopa/carbidopa's effects
The number of subjects receiving COMT inhibitors
concomitant with L-dopa therapy was 12 (52.2%).
Evidence indicates adding COMT inhibitors
to levodopa therapy can reduce the end-of-dose failure patients experience as the effect of levodopa decreases, and also decrease the motor fluctuations (Chan et al., 2008; Damier, Viallet, Ziegler, Bourdeix, & Rerat, 2008).
The claim that this may prevent later motor complications needs to be further substantiated, but there may be a role for early introduction of COMT inhibitors
On the other hand, we found no significant role of COMT inhibitors
in sparing SAM or lowering tHcy in L-dopatreated patients.
The COMT inhibitors
tolcapone and entacapone are other new additions.
They believe that one way could be to offer targeted therapies with drugs like COMT inhibitors
to carriers of the gene.