Efficacy and tolerability of Entacapone versus Cabergoline in parkinsonian patients suffering from wearing-off.

In this 12-wk, multi-center, randomized, open-label, rater-blinded study, efficacy and tolerability of Entacapone (ENT) or Cabergoline (CBG) in conjunction with levodopa were compared in 161 older Parkinson's disease patients with wearing-off. Patients received either ENT, 3 to 5 times daily, or CBG, titrated according to requirements to a maximum of 6 mg/d. A significant decrease of nearly 2 hours in the daily OFF-time (primary efficacy variable) was recorded in both treatment groups. The non-inferiority test failed despite a trend in favor of ENT. Reduction in OFF-time occurred faster in the ENT compared to the CBG treated patients. A decrease of approximately 20% was detected in parts II and III of the UPDRS, with no differences between the groups. Forty-three percent of the patients in the ENT group reported dyskinesias at baseline, and 35% at the final visit. The corresponding figures in the CBG group were 46% and 43%. Quality of life, measured by PDQ-39, increased substantially with both ENT and CBG. The mean daily dosage at the final visit was 698 mg for ENT (plus 447 mg levodopa) and 3.45 mg for CBG (plus 475 mg levodopa). Adverse events (AE), leading to discontinuation, were reported in 8.5% of the ENT and 13.9% of the CBG treated patients. Nausea was the most common AE in each group, corresponding figures being 7.3% with ENT and 25.3% with CBG (P=0.0024). A probable or possible causal relationship with ENT was reported in 41% and with CBG in 64% of the AE. Among these, only one serious AE (dehydration) was recorded with each treatment group. ENT and CBG reduced the patient's motor complications effectively and to a similar degree. The clinical benefit was more quickly apparent with ENT, which also showed a more favorable AE profile than CBG.

Entacapone increases levodopa exposure and reduces plasma levodopa variability when used with Sinemet CR.

Entacapone is a catechol-O-methyltransferase (COMT) inhibitor used as an adjunct to levodopa/dopa decarboxylase inhibitors in the treatment of Parkinson's disease. Entacapone increases the bioavailability and reduces the daily variation of plasma levodopa when administered with standard levodopa preparations. These parameters were studied when entacapone was administered with a controlled-release levodopa preparation after repeated administrations throughout the day in 16 healthy male volunteers. On 2 test days, 200 mg entacapone or placebo was administered 4 times during the day at 4-hour intervals concomitantly with a single dose of controlled-release levodopa/carbidopa 100 mg/25 mg (Sinemet CR). Plasma levodopa, 3-O-methyldopa (3-OMD), and carbidopa concentrations were measured before intake of the medication and then every 30 minutes for 16 hours (until midnight), and less frequently up to 24 hours after the first levodopa dose. The minimum, maximum, and average concentration of levodopa; the daily variation of levodopa concentration; and the area under the time concentration curve (AUC) were calculated. The mean (+/-SD) plasma levodopa AUC was 39% (P = 0.0001) higher with entacapone (11,802 +/- 1454 ng/hour/mL) compared with placebo (8465 +/- 927 ng/hour/mL). The daily variation of plasma levodopa was reduced by about 25% with entacapone (P < 0.01). Entacapone significantly reduced plasma 3-OMD concentration by about 50% (P = 0.0001), indicating marked COMT inhibiting activity. There were no differences in plasma carbidopa concentrations. Entacapone significantly increased the bioavailability of levodopa and reduced its daily variation when administered concomitantly with a controlled-release levodopa preparation.