L-TRYPTOPHAN, 5-HYDROXYTRYPTOPHAN

USES AND ACTIONS

Tryptophan is an essential amino acid and precursor of serotonin. CNS depletion of serotonin is considered to be involved in depression, and tryptophan has a role in the treatment of some cases. Compounding Chemists will compound L-tryptophan or 5-HTP according to individual patient prescriptions, where commercial products are not available. Prescriptions are required for this medication.

ABSORPTION AND METABOLISM

Tryptophan is readily absorbed form the gastrointestinal tract and is extensively bound to serum albumin. It is metabolised to 5-HT then to serotonin and eventually excreted in the urine. Pyridoxine and ascorbic acid are involved in its metabolism.

PRECAUTIONS

Concomitant administration of tryptophan and a MAOI may enhance the effects of the MAOI.

Concomitant administration of tryptophan and melatonin or serotonin reuptake inhibitors may cause serotonin syndrome.

ADVERSE EFFECTS

Nausea, headache, light headedness and drowsiness have been reported.

Occasional: sexual disinhibition, reversible dyskinesias, reversible Parkinson-like rigidity in patients taking tryptophan with or after phenothiazines or benzodiazepines.

5-hydroxytryptophan, an intermediate in the conversion of tryptophan to serotonin, has central stimulant activity as well as reported neurotoxic effects.