Optimization of levodopa therapy.

While there is no single correct starting dose for levodopa therapy, many individuals can be started on either the 25/100 or controlled-release formula, following the general rule not to attempt to titrate carbidopa-levodopa to the point of "normality," which can lead to toxicity. The physician should also determine the proper use of any adjunctive medications; such combined therapy has become the standard approach to treatment. Following the initial period of therapy, emerging difficulties require a reassessment of therapeutic approaches, such as dosage adjustment or introduction of a dopamine agonist. Other possible adverse effects--such as gastrointestinal disorders, orthostatic hypotension, levodopa-induced psychosis, sleep disturbances or parasomnias, or drug interactions--also require carefully monitored individual treatment. Nonpharmacologic concerns can help the Parkinson's disease patient achieve and maintain optimal functioning, including daily exercise, physical therapy, and involvement with support groups.