Ropinirole and pramipexole, the new agonists.

Ropinirole and pramipexole are non-ergoline dopamine agonists which are relatively specific for the D2 family of dopamine receptors. They have side-effect profiles linked to peripheral and central dopaminergic stimulation, amenable to tolerance through a slow titration or the addition of domperidone in sensitive patients. They do not have the uncommon but problematic ergot-related side effects of bromocriptine and pergolide. Ropinirole and pramipexole have both been shown to be efficacious when used as monotherapy in early Parkinson's disease (PD), and have been suggested as being less likely than levodopa to lead to the early development of motor fluctuations and dyskinesias in this clinical setting. They have also been shown to be useful as adjunctive therapy to levodopa in advanced PD and to have a levodopa-sparing effect in these patients. Dose equivalents amongst the available dopamine agonists is difficult to know with certainty but has been estimated as follows: 30 mg of bromocriptine, 15 mg of ropinirole, 4.5 mg of pramipexole, and 3.0 mg of pergolide.