Initial treatment of Parkinson's disease: an update.

OPINION STATEMENT: This is an update to an article published in this journal in 2006, which covered the initial treatment of Parkinson's disease (PD). In this update, we review new research into symptomatic treatments, potential disease modifying ("neuroprotective") agents, and evidence-based reviews of current treatment. We discuss the usage of the MAO-B inhibitors, including the controversy surrounding the possible neuroprotective effects of rasagiline. Usage of extended release formulations of pramipexole and ropinirole, as well as the transdermal dopamine agonist rotigotine, are reviewed. Side effects of the dopamine agonists are discussed, including the cardiac side effects of ergot-derived dopamine agonists, and the impulse control disorders associated with the dopamine agonists. The use of zonisamide as an agent for PD tremor is reviewed. We touch on the clinical research into the benefits of exercise in PD, and briefly review some of the current studies for new formulations of levodopa and other medications and treatments with novel mechanisms of action.