Possible Interaction: 5-Hydroxytryptophan and Carbidopa

“On two different days, we measured blood cortisol level every 15 min for 4 h following the ingestion of L-5-HTP , 0.4 mg/kg, or placebo, both given with carbidopa , a peripheral tryptophan decarboxylase inhibitor, used to prevent peripheral L-5-HTP metabolism before brain absorption.”

“ L-5-HTP with carbidopa dramatically decreased the frequency and intensity of myoclonus, particularly in those patients with a diagnosis of postanoxic intention myoclonus.”

“When L-tryptophan or 5-hydroxytryptophan is administered with phenelzine (a monoamine oxidase inhibitor) and carbidopa (a selective peripheral L-amino acid decarboxylase inhibitor) to raise brain serotonin, a significant increase in myocardial electrical stability is observed.”

“In addition, the authors started 5-hydroxytryptophan titrated to 400 mg orally twice daily with concomittant carbidopa 37.5 mg orally four times a day, and he responded with remission of suicidal ideation and significant improvement in depression and function.”

“ L-5-Hydroxytryptophan , a precursor of serotonin, increases serotonin turnover in the central nervous system when given after carbidopa.”

“We report a case of scleroderma-like illness with unusual pseudobullous morphea and eosinophilia in a patient receiving L-5-hydroxytryptophan and carbidopa ”

“ L-5HTP treatment with and without carbidopa administration increased b-EP levels significantly (p < 0.05).”

“On a regimen of 1 g L-5-HTP and 100 mg l-alpha-methyldopa hydrazine ( carbidopa ), action myoclonus disappeared completely.”

“The plasma concentrations of 5-hydroxytryptophan were increased about ten fold by pretreatment with the decarboxylase inhibitors, carbidopa and benserazide.”

“1-3 In 18 patients with intention myoclonus either due to anoxia or other brain damage, we observed that 61% derived a greater than 50% overall improvement during treatment with L-5HTP in combination with carbidopa.”