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March 1972

Catecholamine Metabolism During Oral Administration of Levodopa: Effects of the Medication in Parkinson's Disease

Author Affiliations

Sydney, New South Wales, Australia
From the divisions of clinical chemistry (Dr. Hinterberger) and neurology (Dr. Andrews), the Prince Henry Hospital, and the School of Medicine, University of New South Wales, Sydney, New South Wales, Australia.

Arch Neurol. 1972;26(3):245-252. doi:10.1001/archneur.1972.00490090071005

After three months of orally administered levodopa, urinary excretion of vanilmandelic acid was moderately increased, but free and conjugated norepinephrine and epinephrine were not significantly affected in 14 patients with Parkinson's disease. The excretion of free and conjugated dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid (HVA) rose one hundred to one thousandfold depending on the daily intake of levodopa. Plasma levels of levodopa attained by 14 patients on similar dosage showed great variations. Low levels of DOPA associated with high levels of acidic metabolites in plasma indicated extensive catabolism of the drug in the alimentary canal or in peripheral organs. Lumbar cerebrospinal fluid levels of HVA measured after three months of treatment in 14 patients were related to the clinical improvement of the patient, and HVA was not detected in two patients who failed to respond.

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