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J Neurol Neurosurg Psychiatry. 1971 December; 34(6): 682–686.
PMCID: PMC1083502

Failure of vitamin B6 to reverse the l-dopa effect in patients on a dopa decarboxylase inhibitor


Seven patients with Parkinsonism previously on l-dopa were placed on a regimen of l-dopa and alpha methyl dopa hydrazine (a dopa decarboxylase inhibitor). Two of these patients had previously shown marked clinical deterioration of the l-dopa improvement when given pyridoxine. None of the seven patients receiving alpha methyl dopa hydrazine demonstrated any change in their condition when given pyridoxine. The failure of vitamin B6 to reverse the clinical effect of l-dopa in patients receiving both l-dopa and a peripheral dopa decarboxylase inhibitor suggests that reversal of the l-dopa effect induced by vitamin B6 is due to increasing the activity of the enzyme dopa decarboxylase outside the central nervous system.

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Selected References

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  • Bartholini G, Pletscher A, Tissot R. On the origin of homovanillic acid in the cerebrospinal fluid. Experientia. 1966 Sep 15;22(9):609–610. [PubMed]
  • Bartholini G, Burkard WP, Pletscher A. Increase of cerebral catecholamines caused by 3,4-dihydroxyphenylalanine after inhibition of peripheral decarboxylase. Nature. 1967 Aug 19;215(5103):852–853. [PubMed]
  • Bertler A, Falck B, Owman C, Rosengrenn E. The localization of monoaminergic blood-brain barrier mechanisms. Pharmacol Rev. 1966 Mar;18(1):369–385. [PubMed]
  • Bowers MB., Jr Cerebrospinal fluid 5-hydroxyindoles and behavior after L-tryptophan and pyridoxine adminstration to psychiatric patients. Neuropharmacology. 1970 Nov;9(6):599–604. [PubMed]
  • CANTER GJ, DE LA TORRE R, MIER M. A method for evaluating disability in patients with Parkinson's disease. J Nerv Ment Dis. 1961 Aug;133:143–147. [PubMed]
  • Cotzias GC, Papavasiliou PS, Gellene R. Modification of Parkinsonism--chronic treatment with L-dopa. N Engl J Med. 1969 Feb 13;280(7):337–345. [PubMed]
  • Crane GE, Turek IS, Kurland AA. Failure of pyridoxine to reduce drug-induced dyskinesias. J Neurol Neurosurg Psychiatry. 1970 Aug;33(4):511–512. [PMC free article] [PubMed]
  • DEGKWITZ R, FROWEIN R, KULENKAMPFF C, MOHS U. [On the effects of L-dopa in man and their modification by reserpine, chlorpromazine, iproniazid and vitamin B6]. Klin Wochenschr. 1960 Feb 1;38:120–123. [PubMed]
  • Duvoisin RC, Yahr MD, Coté LD. Pyridoxine reversal of L-dopa effects in Parkinsonism. Trans Am Neurol Assoc. 1969;94:81–84. [PubMed]
  • Ebadi MS, Bostad R, Pellegrino RJ. Impairment of pyridoxal phosphate dependent metabolic reactions in a child with subacute necrotizing encephalopathy. J Neurol Neurosurg Psychiatry. 1969 Oct;32(5):393–398. [PMC free article] [PubMed]
  • Gibbs DA, Watts RW. The action of pyridoxine in primary hyperoxaluria. Clin Sci. 1969 Oct;37(2):565–565. [PubMed]
  • Hoehn MM, Yahr MD. Parkinsonism: onset, progression and mortality. Neurology. 1967 May;17(5):427–442. [PubMed]
  • Hornykiewicz O. Dopamine (3-hydroxytyramine) and brain function. Pharmacol Rev. 1966 Jun;18(2):925–964. [PubMed]
  • JACOB F, MONOD J. Genetic regulatory mechanisms in the synthesis of proteins. J Mol Biol. 1961 Jun;3:318–356. [PubMed]
  • Klawans HL., Jr The pharmacology of parkinsonism (a review). Dis Nerv Syst. 1968 Dec;29(12):805–816. [PubMed]
  • Klawans HL., Jr A pharmacologic analysis of Huntington's chorea. Eur Neurol. 1970;4(3):148–163. [PubMed]
  • Klawans H, Jr, Ilahi MM, Shenker D. Theoretical implications of the use of L-dopa in parkinsonism. A review. Acta Neurol Scand. 1970;46(4):409–441. [PubMed]
  • LOVENBERG W, WEISSBACH H, UDENFRIEND S. Aromatic L-amino acid decarboxylase. J Biol Chem. 1962 Jan;237:89–93. [PubMed]
  • MONOD J, CHANGEUX JP, JACOB F. Allosteric proteins and cellular control systems. J Mol Biol. 1963 Apr;6:306–329. [PubMed]
  • Pletscher A, Bartholini G, Tissot R. Metabolic fate of l-[14C] DOPA in cerebrospinal fluid and blood plasma of humans. Brain Res. 1967 Feb;4(1):106–109. [PubMed]
  • Sourkes TL. Dopa decarboxylase: substrates, coenzyme, inhibitors. Pharmacol Rev. 1966 Mar;18(1):53–60. [PubMed]
  • Tissot R, Gaillard JM, Guggisberg M, Gauthier G, de Ajuriaguerra J. Thérapeutique du syndrome de Parkinson par la L-Dopa "per os" associée à un inhibiteur de la décarbosylase (Ro IV 46.02) Presse Med. 1969 Apr 5;77(17):619–622. [PubMed]
  • Weiner W, Harrison W, Klawans H. L-dopa and cerebrospinal fluid homovanillic acid in Parkinsonism. Life Sci. 1969 Sep 1;8(17):971–976. [PubMed]
  • Yahr MD, Duvoisin RC, Schear MJ, Barrett RE, Hoehn MM. Treatment of parkinsonism with levodopa. Arch Neurol. 1969 Oct;21(4):343–354. [PubMed]

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