Ropinirole, a non-
ergoline dopamine agonist, has selective affinity for
dopamine D2-like receptors and little or no affinity for non-dopaminergic brain receptors.
Ropinirole is indicated as adjunct
therapy to
levodopa in patients with advanced
Parkinson's disease. It is also indicated, and recent clinical trials have focused on its use, as monotherapy in patients with early
Parkinson's disease. In the symptomatic treatment of early
Parkinson's disease ropinirole monotherapy was significantly more effective than placebo in 2 multicentre, randomised, double-blind trials of 3 to 12 months duration as assessed by the Unified Parkinson's Disease Rating Scale (UPDRS) motor scores and Clinical Global Impression/Clinical Global Evaluation Scales. In a similarly designed 3-year comparative study with
bromocriptine,
ropinirole recipients showed a significant improvement in UPDRS-
activities of daily living (
ADL) scores; however, motor scores were similar between the 2 groups.
Ropinirole and
levodopa treatments were similar in efficacy as measured by UPDRS
ADL scores, although
ropinirole recipients showed significantly less improvement on UPDRS motor scores at the 5-year study end-point in a multicentre, randomised double-blind trial. As an adjunct
therapy to
levodopa in patients with more advanced
Parkinson's disease,
ropinirole was reported to be as effective as
bromocriptine and significantly more effective than placebo. In general in the comparisons with placebo
ropinirole allowed a > or =20% reduction in the concomitant dose of
levodopa without compromising efficacy in a significant proportion of patients and, in some trials decreased the amount of awake time spent in the 'off' state ('off' state is defined as a gradual return to
parkinsonism despite adequate medication).
Ropinirole was well tolerated either as monotherapy or as an adjunct to
levodopa treatment.
Nausea,
dizziness and
somnolence were the most commonly reported adverse events and were reported at a higher incidence by patients receiving
ropinirole than by those receiving placebo. In patients with early
Parkinson's disease,
ropinirole generally showed a similar overall tolerability profile to
bromocriptine although, over a 3-year period
nausea was more commonly reported with
ropinirole recipients. In a 5-year study, the incidence of
dyskinesia was significantly lower with
ropinirole than with
levodopa regardless of
levodopa supplementation. Prior to the addition of supplementary
levodopa 5% of
ropinirole recipients had experienced
dyskinesia compared with 36% of those receiving
levodopa.
CONCLUSIONS: