Ropinirole - A review of its use in the management of Parkinson's disease

Ropinirole, a non-ergoline dopamine agonist, has selective affinity for dop amine D-2-like receptors and little or no affinity for non-dogaminergic bra in receptors, Ropinirole is indicated as adjunct therapy to levodopa in pat ients with advanced Parkinson's disease. It is also indicated, and recent c linical trials have focused on its use, as monotherapy in patients with ear ly Parkinson's disease. In the symptomatic treatment of early Parkinson's disease ropinirole monoth erapy was significantly more effective than placebo in 2 multicentre, rando mised, double-blind trials of 3 to 12 months duration as assessed by the Un ified Parkinson's Disease Rating Scale (UPDRS) motor scores and Clinical Gl obal 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 lev odopa treatments were similar in efficacy as measured by UPDRS ADL scores, although ropinirole recipients showed significantly less improvement on UPD RS 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 wi th placebo ropinirole allowed a greater than or equal to 20% reduction in t he concomitant dose of levodopa without compromising efficacy in a signific ant proportion of patients and, in some trials decreased the amount of awak e 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 lev odopa treatment. Nausea, dizziness and somnolence were the most commonly re ported adverse events and were reported at a higher incidence by patients r eceiving ropinirole than by those receiving placebo. In patients with early Parkinson's disease, ropinirole generally showed a similar overall tolerab ility profile to bromocriptine although, over a 3-year period nausea was mo re commonly reported with ropinirole recipients, In a 5-year study, the inc idence of dyskinesia was significantly lower with ropinirole than with levo dopa regardless of levodopa supplementation. Prior to the addition of suppl ementary levodopa 5% of ropinirole recipients had experienced dyskinesia co mpared with 36% of those receiving levodopa. Conclusions: In patients with early Parkinson's disease, ropinirole monothe rapy was more efficacious than bromocriptine with regard to improvement in activities of daily living, and need for supplemental levodopa, Ropinirole recipients had a higher requirement for levodopa supplementation than levod opa recipients in a 5-year study, but the incidence of dyskinesia was signi ficantly lower with ropinirole than with levodopa (markedly so in the one t hird of ropinirole recipients who were able to remain on monotherapy with n o levodopa supplementation). Thus available data suggest that ropinirole ma y provide a means of treating early Parkinson's disease while minimising th e risk of dyskinesia and delaying the need for supplemental levodopa in som e patients. In addition, ropinirole is also efficacious in the management o f more advanced Parkinson's disease in patients who are experiencing motor complications after long term levodopa use.