Dopamine Agonist Therapy in Advanced Parkinson’s Disease

“Parkinson’s disease (PD) doesn’t kill you, it takes your life away.” This is a disturbing quotation by the English Parkinson Lay Organisation. There is, however, no other neurodegenerative disease which responds better to treatment than PD. Treatment of advanced PD is located between these poles (Figure 1). Most national guidelines and papers on the treatment of PD recommended that early phases are treated with dopamine agonists and monoamineoxidase B inhibitors and late phases with levo-dopa. Common guidelines and publications regarding the treatment of late phase PD have thus not yet focused on dopamine agonists. This appears somewhat surprising because nowadays most patients commence treatment with a dopamine agonist. Strategic management of PD has to take into consideration the following points: 1) many patients will receive therapy for 15-20 years, 2) PD should be managed optimally throughout its course, 3) the aim of strategic management is to maintain efficacy and minimize side-effects in both the short and long term, and 4) initial therapy should be sustained for the long-term therapy. These criteria demand that treatment is initiated with efficacious and safe drugs and dopamine agonists meet this request. The main reason for their use is, however, that due to its short plasma half-life, levo-dopa induces dyskinesia. Conversely, dopamine agonists have longer half-lives and therefore stimulate dopamine receptors in a more tonic, continuous way, thus avoiding or at least decreasing the occurrence and severity of dyskinesia. It is for fear of the risk of developing side effects such as hallucinations, psychosis, orthostatic hypotension, nausea and vomiting that dopamine agonists are not normally used in advanced stages, rather than their loss of efficacy. For this reason, it would be most helpful to have measures to identify those patients with a high tolerance of dopamine agonists, in order to either allow them to continue with dopamine agonist therapy for as long as possible, or to add dopamine agonists in advanced stages. This review will briefly consider these options and will conclude that it may be beneficial to use modern dopamine agonists such as ropinirole slow release (Modutab) or the rotigotine patch, even in the elderly or in advanced PD patients.