title: Tryptophan loading may reverse tolerance to opiate analgesics in humans: a preliminary report.
abstract: Five patients on chronic opiate medication to treat low-back and leg pain were determined to have developed opiate tolerance on the basis of their failure to obtain significant relief (rated on a subjective pain scale and by the degree of straight leg-raising they were able to endure) after receiving 30 mg of morphine administered i.v. in divided doses over 35 min. After these patients' diets had been supplemented with 4 g/day of L-tryptophan for 2-9 weeks, they achieved significant relief from pain when the opiate tolerance test was re-administered, and were able to lead more active lives while reducing their daily opiate intake. chronic opiate administration probably reduces the serotonin turnover rate in the central nervous system; it may be that this is reversed by loading with the serotonin precursor, L-tryptophan.
mesh_terms: D001794:Blood Pressure / Q000187:drug effects; D004032:Diet; D004361:Drug Tolerance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009294:Narcotics / Q000494:pharmacology*; D010146:Pain / Q000503:physiopathology; D011674:Pulse / Q000187:drug effects; D012119:Respiration / Q000187:drug effects; D014364:Tryptophan / Q000494:pharmacology*
chemical_list: D009294:Narcotics; D014364:Tryptophan