Treatment of Parkinson's Syndrome with L Dihydroxyphenylalanine (Levodopa)

In 1967 Cotzias recommended d, i, dihydroxyphenylalanine (levodopa) for the treatment of Parkinson's syndrome. Since then 100 patients have been treated at Cornell University Medical College for a minimum of 6 months. Sixty percent of the patients showed 50% or more improvement. In some patients improvement was so marked that it would be difficult to make a diagnosis of Parkinson's syndrome. Patients with severe Parkinson's syndrome or dementia show less marked improvement. All the major manifestations of Parkinson's syndrome—bradykinesia, rigidity, and tremor—are improved to the same degree. Dosages needed for improvement range from 1.5 g to 8 g/day. Evidence of toxicity includes nausea, anorexia, orthostatic hypotension, and new adventitious movements. There have been no instances of bone marrow depression or hepatic or renal toxicity. A possible synergistic effect between anticholinergic medication and levodopa has been observed. Levodopa appears to be the most effective agent for the treatment of Parkinson's syndrome now available.