Effects of L-tryptophan on the effects of antitussives.
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L-tryptophan can be considered to be a useful constituent of antitussive preparations and the liability with respect to physical dependence on dihydrocodeine was not enhanced by the simultaneous administration of L-t Kryptophan.Abstract:
The effects of L-tryptophan and the major constituents of cough medicines on the antitussive effect of dihydrocodeine were examined in a comparative study with anesthetized rats. The antitussive effect of dihydrocodeine was enhanced by simultaneous administration of noscapine or methylephedrine. In rats treated with noscapine and methylephedrine together, the effect of dihydrocodeine was more markedly enhanced. Furthermore, L-tryptophan reduced by half the antitussive ED50 (AtD50) of dihydrocodeine. There was no difference between the AtD50 of dihydrocodeine when administered in combination with noscapine and methylephedrine and that of dihydrocodeine when combined with noscapine and L-tryptophan. The AtD50 of noscapine and dextromethorphan was also reduced by about half when what was administered with L-tryptophan. By contrast, the liability with respect to physical dependence on dihydrocodeine was not enhanced by the simultaneous administration of L-tryptophan. These results suggest that L-tryptophan can be considered to be a useful constituent of antitussive preparations.read more
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Book ChapterDOI
Central mechanisms II: pharmacology of brainstem pathways.
TL;DR: Understanding of the mechanisms of action of antitussive drugs would be significantly advanced by further work in the medullary areas, including the nucleus of the tractus solitarius (NTS) and the caudal ventrolateral respiratory column.
Journal ArticleDOI
The Importance of Quality Specifications in Safety Assessments of Amino Acids: The Cases of l-Tryptophan and l-Citrulline.
TL;DR: This review examines 2 amino acids that have been associated with in-market adverse events to show how quality specifications might have helped prevent the adverse clinical outcomes and highlights the importance of various factors that should be incorporated into an overall safety assessment.
Journal ArticleDOI
Effects of L-Tryptophan on the Development of Tolerance to the Antitussive Effects of Dihydrocodeine
TL;DR: It is concluded that L-tryptophan may antagonized the development of tolerance to the antitussive effects of dihydrocodeine.
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