The pharmacokinetics of L‐tryptophan following its intravenous and oral administration.

The pharmacokinetics of L‐tryptophan (5 g and 7.5 g) have been studied after its intravenous administration to healthy subjects and the results compared with those obtained after oral administration (0.7 g‐ 3.5 g). In order to do this, we have re‐analysed previously published data relating to oral administration. The data obtained following the oral administration of L‐tryptophan suggest that the total body clearance and apparent volume of distribution are saturable. The pharmacokinetics of tryptophan after intravenous administration of 5 g and 7.5 g were similar to those after the oral administration of 25 and 50 mg kg‐1 (i.e. 1.75 g and 3.5 g). Similar pharmacokinetic values were obtained following intravenous tryptophan when the same subjects were retested after a period of 2‐4 weeks. 1985 The British Pharmacological Society