Parkinson's disease: drug therapy.

Unlike the situation in patients with most other degenerative neurological disorders, individuals with Parkinson's disease (PD) and their physicians have a wide range of effective symptomatic drugs at their disposal. All have somewhat differing indications, potencies and side-effects, and treatment needs to be individualized and also altered as the disease and the duration of drug treatment progress and the patient ages. The main problem for most patients after prolonged treatment with L-dopa is the longterm L-dopa syndrome. Fluctuations and dyskinesias are usually the principal complaint in younger, and neuropsychiatric symptoms in older, patients. Although L-dopa is the 'gold standard' in terms of efficacy, these treatment-related problems make it necessary to regularly monitor patients' response to treatment and if necessary to modify their drug regime accordingly and, particularly in younger patients, to devise treatment strategies whereby the use of L-dopa can be limited or delayed. Currently available alternative or adjunctive treatments to L-dopa preparations include oral dopamine agonists, subcutaneous apomorphine, amantadine, selegiline and anticholinergics, and some guidelines about how and when to use all of these drugs or classes of drugs are presented in this chapter. Despite initial claims of neuroprotection by selegiline, we are still awaiting the more promising second era of drug treatment for PD, whereby hopefully we can retard, halt or prevent the disease itself.