Pramipexole extended-release: a review of its use in patients with Parkinson's disease

Pramipexole, a non-ergolinic, D3-preferring dopamine agonist (DA), is well established as a treatment option for motor symptoms at all stages of Parkinson's disease (PD). It is administered orally and is available as both a three-times daily immediate-release (IR) formulation and a once-daily extended-release (ER) formulation (Mirapex(®) ER, Mirapexin(®) ER; Pexola(®) ER, Sifrol(®) ER). The two formulations are bioequivalent; the majority (>80 %) of patients can be switched overnight from pramipexole IR to ER without the need for dosage adjustment. In terms of improving activities of daily living and motor function in short-term (≤33-week), double-blind studies, pramipexole ER was noninferior to pramipexole IR and significantly more effective than placebo as monotherapy in patients with early PD, and similar to pramipexole IR and significantly more effective than placebo as adjunctive therapy to levodopa in patients with advanced PD. In long-term (80-week) extensions of these trials, open-label treatment with pramipexole ER was associated with sustained symptomatic benefit. Moreover, the majority of extension participants who responded to a simple convenience questionnaire expressed a preference for once-daily over three-times daily dosing. Pramipexole ER was generally well tolerated in clinical trials; no new or unexpected safety signals were identified compared with the IR formulation. Head-to-head trials are needed in order to fully define the role of pramipexole ER relative to other once-daily formulations of DAs (oral ropinirole and transdermal rotigotine). Nonetheless, by reducing the pill burden, the ER formulation of pramipexole provides a more convenient alternative to the IR formulation; studies specifically testing whether this translates into improved patient compliance and symptom control are worthwhile.