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| Interactions
with Phenylalanine | |
| Baclofen
In situ, phenylalanine (up to 100 mM) decreased the absorption of isotonic
perfusion solutions of baclofen (0.5 mM) in the rat small intestine by 67%
(Cejudo-Ferragud et al. 1996). To maximize absorption of the drug, baclofen
should not be administered with meals, especially meals high in protein content.
18F-DOPA
Infusion of L-phenylalanine prior to administration of
3-O-methyl-6-[18F]fluoro-L-DOPA (18F-DOPA) prevented 18F-DOPA uptake in the
brain (Doudet et al. 1992). L-phenylalanine improved specific-to-non-specific
contrast images of 18F-DOPA during positron emission tomography (PET)
scanning. Levodopa
Administration of levodopa (1 mg/kg/hour IV) following administration of
phenylalanine (100 or 200 mg/kg po) in two patients with advanced Parkinson's
disease altered the clinical effects of the drug (Woodward, et al. 1998). The
therapeutic response to levodopa could be diminished when administered at the
same time as phenylalanine. |
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| References |
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|
Cejudo-Ferragud E, Nacher A, Polache A, Cercos-Fortea T, Merino M, Casabo VG.
Evidence of competitive inhibition for the intestinal absorption of baclofen by
phenylalanine, Int J of Pharm (Amsterdam). 1996;132:63-69.
Doudet D, McLellan CA, Aigner TG, Wyatt RJ, Cohen RM. Delayed L-phenylalanine
infusion allows for simultaneous kinetic analysis and improved evaluation of
specific-to-non-specific fluorine-18-DOPA uptake in brain. J of Nucl Med.
1992;33(7):1383-1389.
Woodward, WR, Olanow CW, Beckner Rm et al. The effect of L-dopa infusions
with and without phenylalanine challenges in parkinsonian patients.
Neurol. 1998;48:1704-1708. |
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Copyright © 2000 Integrative Medicine
Communications This publication contains
information relating to general principles
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