Levodopa (LD) is the gold standard of therapy for Parkinson's disease, but it is commonly associated with motor fluctuations and dyskinesias. Dopamine agonists are often used as adjuncts to LD in an attempt to reduce these complications. In this open-label study the authors investigated the effects of high doses of adjunctive ropinirole in 36 patients with advanced Parkinson's disease and normal cognitive status. The daily dose of ropinirole was increased from 18.4 +/- 3.5 mg to 34.7 +/- 5.5 mg, generally in four separate doses. The daily LD dose was decreased from 734.1 +/- 254.8 mg to 502.8 +/- 228.4 mg. After 12 months 25 patients were still on high doses of ropinirole whereas 11 patients had, after either the emergence of side effects or a worsening of their clinical conditions, decreased or interrupted ropinirole. At 12 months, the daily doses of LD and ropinirole were 489 +/- 243 mg and 34.6 +/- 4.6 mg respectively. There was a significant reduction in the Dyskinesia Rating Scale scores during both ON and OFF periods, indicating a reduction in dyskinesias during ON periods and a reduction in dystonias during OFF periods (p < 0.001). Both the intensity and the hours spent during OFF periods were reduced significantly (p < 0.001). Even though these results need to be confirmed through extended controlled studies, the high-dose dopamine agonist strategy is safe for patients with advanced PD in whom a marked motor response to LD (even at very low doses) is associated with severe dyskinesias, and may be used as a means of delaying surgery or as an alternative to continuous apomorphine infusion.