title: 5-HT uptake inhibitors and tricyclic antidepressants: relation between tryptophan availability and clinical response in depressed patients.
abstract: The amount of tryptophan (Trp) available for transport from plasma into the brain was estimated in patients with major depression before treatment for 4 weeks with a 5-HT potentiating tricyclic antidepressant (TCA), amitriptyline (n = 21) or clomipramine (n = 17), or a selective 5-HT uptake inhibitor, citalopram (n = 14) or paroxetine (n = 27). The ratio in plasma of Trp to the sum of the other large neutral amino acids (LNAA) was significantly inversely correlated with improvement on TCA, and patients with ratio Trp/LNAA below the mean improved significantly more than patients with a higher ratio but with comparable serum steady-state drug levels. The Trp concentration was a bit stronger inversely correlated with improvement on 5-HT uptake inhibitors than the ratio Trp/LNAA, and patients with Trp level below the mean improved significantly more than those with a higher level but with comparable serum steady-state drug levels. Plasma amino acid variables may be a useful tool for increasing the efficacy of antidepressant treatment.
authors: Clinical Research Laboratory, St. Hans Hospital, Roskilde, Denmark.
authors: S E
authors: SE
authors: Møller
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000929:Antidepressive Agents, Tricyclic / Q000627:therapeutic use*; D003866:Depressive Disorder / Q000188:drug therapy* / Q000378:metabolism / Q000523:psychology; D006801:Humans; D011569:Psychiatric Status Rating Scales; D012702:Serotonin Antagonists / Q000627:therapeutic use*; D014364:Tryptophan / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000596:Amino Acids; D000929:Antidepressive Agents, Tricyclic; D012702:Serotonin Antagonists; D014364:Tryptophan