Treatment of Parkinson's disease. From theory to practice.

Parkinson's disease responds rather dramatically to levodopa therapy during the first several years of treatment. With advancing disease, however, symptom control becomes more erratic, and some symptoms may become refractory to treatment. The use of selegiline hydrochloride (Eldepryl) has been proposed to slow the progression of Parkinson's disease; however, current evidence suggests that it is only partially effective at best, and there is no definite proof of a neuroprotective effect. Nonetheless, it is a reasonable treatment choice. Carbidopa-levodopa (Sinemet) remains the foundation of symptomatic treatment of Parkinson's disease. Clinical fluctuations occurring with advancing disease may be at least partially controlled by appropriate adjustments in dosage. A direct-acting dopamine agonist, bromocriptine mesylate (Parlodel) or pergolide mesylate (Permax), can be very helpful as adjunctive therapy to smooth these clinical fluctuations. Excessive intracellular oxidative stress has been proposed as a cause of Parkinson's disease; however, a recent multicenter trial investigating the use of high doses of the antioxidant vitamin E showed it to be ineffective. Whether other forms of nonspecific antioxidant therapy will prove beneficial is open to speculation.