Phenylalanine - Benserazide, Levodopa Interaction Details

Interaction Details

Benserazide, Levodopa is classified as belonging to the following category: Levodopa

Phenylalanine, especially in high doses, can reduce the effectiveness of levodopa.
Phenylalanine competes with levodopa for carrier-mediated transport into the brain. The resulting reduction in levels of levodopa in the brain can exacerbate tremor, rigidity, and the "on-off" phenomenon in patients with Parkinson disease.

Interaction Rating

Major

Likelihood of Occurrence

Probable

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.

References

Nutt JG, Woodward WR, Hammerstad JP, et al. The "on-off" phenomenon in Parkinson's disease. Relation to levodopa absorption and transport. N Engl J Med 1984;310:483-8.
Eriksson T, Granerus AK, Linde A, et al. "On-off" phenomenon in Parkinson's disease: relationship between dopa and other large neutral amino acids in plasma. Neurology 1988;38:1245-8.

Phenylalanine - More Interactions

Phenylalanine interacts with 16 drugs

Interaction Rating Key

These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.

Major	The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur.
Moderate	Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur.
Minor	Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction.
Unknown	No interactions have been reported or no interaction data is currently available.