Therapeutic Response to Pramipexole in a Patient with Multiple System Atrophy with Predominant Parkinsonism: Positron Emission Tomography and Pharmacokinetic Assessments

Abstract

Multiple system atrophy with predominant parkinsonism (MSA-P) usually shows poor responsiveness to dopaminergic medications. We herein describe a patient with MSA-P who exhibited a good response to pramipexole but not to an ordinary dose of L-dopa. Positron emission tomography (PET) displayed severely impaired presynaptic dopaminergic availability and relatively preserved postsynaptic D2 receptor binding capacity. The pharmacokinetic analyses demonstrated relatively low bioavailability for L-dopa and adequate plasma levels of pramipexole, even at baseline, on a stable daily dose. The PET features and pharmacokinetic differences between L-dopa and pramipexole indicate the presence of unique therapeutic responses to dopaminergic medications in the patient.

The putaminal abnormalities on 3.0T magnetic resonance imaging: can they separate parkinsonism-predominant multiple system atrophy from Parkinson's disease?

“…Parkinsonism-predominant multiple system atrophy (MSA-P), a subtype of multiple system atrophy, is a sporadic neurodegenerative disorder with symptoms that are characteristic of parkinsonism, cerebellar ataxia, and autonomic dysfunction, etc. It is important to emphasize the need for precise diagnostic differentiation between MSA-P and Parkinson's disease (PD), because they differ in prognosis and treatment response and some new surgical and pharmacologic therapies may work only in patients with PD (1).…”

Novel Therapies for Parkinsonian Syndromes–Recent Progress and Future Perspectives

“…However, only 6 out of 7 participants completed this study, and its protocol did not include placebo-controlled group. Another clinical trial showed improvement after pramipexol administration among MSA patients with no response to levodopa; however, this is only a single report (Ueda et al, 2013). In a study evaluating the effectiveness of amantadine (100 mg twice daily) in PSP and MSA, 42.9% of the PSP patients and 61.5% of the MSA patients showed partial improvement (Rajrut et al, 1997).…”