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Effects of L-tryptophan on the development of tolerance to the antitussive effects of dihydrocodeine
1Department of Pharmacology, School of Pharmacy, Hoshi University, Tokyo, Japan.
Japanese Journal of Pharmacology
|March 1, 1991
Abstract:
The effects of L-tryptophan on the development of tolerance to the antitussive effects of dihydrocodeine were examined in rats. Chronic co-administration of L-tryptophan with dihydrocodeine prevented the development of tolerance to the antitussive effects of dihydrocodeine. Furthermore, the antitussive effects of dihydrocodeine in dihydrocodeine-tolerant rats were fully restored by acute co-administration of L-tryptophan, as evidenced by a decrease of about 50% in the ED50 value of dihydrocodeine. Thus, it is concluded that L-tryptophan may antagonized the development of tolerance to the antitussive effects of dihydrocodeine.