Pharmacologic profile of ropinirole: a nonergoline dopamine agonist

The use of dopamine agonists as monotherapy or in combination with levodopa in the treatment of Parkinson's disease (PD) allows for reduction or limitation of the levodopa dose, potentially delaying the onset or reducing the severity of late motor complications. Ropinirole is a new nonergoline dopamine agonist that binds specifically to D2-like receptors with a selectivity similar to that of dopamine (D3 > D2 > D4). The chemical structure of ropinirole has the potential to maintain a structure-activity relationship similar to that of dopamine and other effective dopamine agonists without producing ergot-related adverse effects. Ropinirole has demonstrated efficacy in two standard preclinical models of PD and has shown a very low propensity to induce dyskinesia in these studies. This latter property is of potential clinical importance for pharmacotherapy of early PD. This article will present the importance of pharmacologic specificity of dopamine agonists along with the basic pharmacologic characteristics of ropinirole that may contribute to its efficacy in the treatment of PD.