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.