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Discover Supplement-Drug Interactions

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Last Updated: a year ago

Possible Interaction: Levodopa and Phenylalanine



Research Papers that Mention the Interaction

Phenylalanine , a large neutral amino acid (LNAA) competing with levodopa for transport across the blood-brain barrier, reduced the hypotensive and antiparkinsonian effects of levodopa.
Clinical neuropharmacology  •  1992  |  View Paper
Dietary restriction of phenylalanine and oral administration of amine precursors, L-dopa and 5-hydroxytryptophan had poor efficiency on epilepsy and psychomotor delay.
Archives de pediatrie : organe officiel de la Societe francaise de pediatrie  •  1999  |  View Paper
These observations suggest that either L-dopa entry into CSFV and the brain are differentially affected by phenylalanine or that phenylalanine affects other steps in the motor response.
Neurology  •  1993  |  View Paper
Furthermore, the clinical and biochemical effects of L-dopa were inhibited by phenylalanine and 5-HTP, respectively, demonstrating that these amino acids have antagonistic pharmacological effects.
The Journal of clinical investigation  •  1984  |  View Paper
High-protein meals or oral phenylalanine , leucine, or isoleucine (100 mg per kilogram of body weight) reversed the therapeutic effect of infused levodopa without reducing plasma levodopa concentrations.
The New England journal of medicine  •  1984  |  View Paper
L-DOPA , when given with L-phenylalanine , reduced the absorption rate of this amino acid.
This effect was only seen when L-DOPA and L-phenylalanine were given simultaneously.
Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine  •  1971  |  View Paper
L-DOPA preloading induced a massive increase of BPA concentration either in vitro on C6 glioma cells or in vivo in the animal model tumour.
Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine  •  2009  |  View Paper
Further, synthesis of DA from l-DOPA was decreased in the presence of the amino acids tyrosine, phenylalanine and tryptophan, whereas the amino acids glycine and proline were without any significant effect.
Placenta  •  2007  |  View Paper
L-Dopa uptake and conversion to DA was competitively inhibited by other aromatic amino acids (Tyr and Phe).
Renal physiology and biochemistry  •  1994  |  View Paper
In presence of quassin phenylalanine , tyrosine and L-dopa levels were increased in larvae.
Indian journal of biochemistry & biophysics  •  1992  |  View Paper
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