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Original Contributions
Feberuary 1973

Modification of Levodopa Effect by Systemic Decarboxylase Inhibition

Author Affiliations


From the Division of Medicine, Department of Neurology, Mt. Sinai Hospital, Case Western Reserve University, Cleveland.

Arch Neurol. 1973;28(2):91-95. doi:10.1001/archneur.1973.00490200039004

Twenty-five parkinsonian patients, previously receiving chronic levodopa therapy, were treated with a combination of levodopa and the peripheral carboxylase inhibitor, α-methyl dopa hydrazine (MK486). There resulted a 60% to 70% decrease in daily levodopa requirements, and a mean 51.7% enhancement of clinical response to the amino acid. Adverse side effects of systemic origin were decreased. Cardiac arrhythmias were detected in six of 19 patients receiving levodopa alone. All showed improvement in cardiac rhythmicity.

Blood dopa levels following oral administration of 250 mg of levodopa were potentiated sevenfold by 50 mg of MK-486. The blood dopa-dopamine ratio increased from 11.5 to 62.2. All changes were statistically significant at the P <.001 level.

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