Budipine Hydrochloride

Although resting tremor is the most identifiable sign of Parkinson's disease, its underlying basis appears to be the most complex of the cardinal signs. The variable relationship of resting tremor to other symptoms of PD has implications for diagnosis, prognosis, medical and surgical treatment. Structural lesions very rarely cause classic resting tremor, with likely contributions to tremor by a network of neurons both within and outside the basal ganglia. Patients with only resting tremor show dopaminergic deficits with radioligand imaging, but severity of tremor correlates poorly in such dopamine imaging studies. Correlation of tremor severity to changes in radioligand studies is also limited by the use of mostly qualitative measures of tremor severity. A complex pharmacologic basis of parkinsonian resting tremor is supported by treatment studies. Although levodopa is clearly effective for resting tremor, several agents have shown efficacy that appears to be superior or additive to that of levodopa including anticholinergics, clozapine, pramipexole, and budipine. Although the thalamus has the greatest body of evidence supporting its role as an effective target for surgical treatment of tremor, recent studies suggest that the subthalamic nucleus may be a reasonable alternative target for patients with Parkinson's disease and severe tremor as the predominant symptom. © 2007 Movement Disorder Society

Publisher Summary This chapter focuses on antiglutamatergic drugs in the treatment of Parkinson's disease (PD). In the vertebrate brain, glutamate is the main excitatory neurotransmitter and mediates neurotransmission of most excitatory synapses. Glutamate-mediated synaptic transmission is essential for the normal functioning of the central nervous system. The ideal antiglutamatergic drug should largely be able to block the N-methyl-D-aspartate (NMDA) receptor in situations of excessive activation but without altering glutamatergic transmission during normal conditions. Amantadine is the only antiglutamatergic agent used in the management of PD patients and is particularly useful for the treatment of levodopa-induced dykinesias. Amantadine interacts with several different neurotransmitters systems and exhibits dopaminergic and anticholinergic properties along with antagonist activity of NMDA glutamatergic receptors. Amantadine exhibits mild antiparkinsonian effect and is more effective in the control of bradykinesia and rigidity than in tremor. It also exhibits neuroprotective properties in addition to its symptomatic effects. The chapter also describes some other antiglutamatergic drugs, namely memantine, dextromethorphan, budipine, and riluzole.