Effects of clomipramine on plasma amino acids and serotonergic parameters in panic disorder and depression

Eur Neuropsychopharmacol. 1997 Aug;7(3):235-9. doi: 10.1016/s0924-977x(97)00412-4.


We examined the effects of long-term (six months) treatment with the serotonin potentiating tricyclic antidepressant clomipramine on several serotonergic parameters in panic disorder and depressive patients. Serotonin (5-HT) levels in blood, platelets and plasma were significantly reduced to 4%, 3% and 28% of their respective baseline values. In addition, the plasma level of tryptophan was also significantly reduced, although the decrease was only 16%. Three months after discontinuation of clomipramine treatment, 5-HT in blood and platelets reached baseline values again, while the plasma 5-HT level was still reduced to 68% of pretreatment values. Unexpectedly, the plasma tryptophan concentration was even lower at this time-point than after six months of treatment. These results show that clomipramine not only has an effect on 5-HT levels in blood, platelets and plasma, but also on plasma tryptophan concentration. We speculate that low plasma tryptophan after treatment may constitute a risk for the recurrence of psychopathology.

Publication types

  • Clinical Trial

MeSH terms

  • Adult
  • Amino Acids / blood*
  • Antidepressive Agents, Tricyclic / pharmacology*
  • Antidepressive Agents, Tricyclic / therapeutic use*
  • Blood Platelets / drug effects
  • Blood Platelets / metabolism
  • Clomipramine / pharmacology*
  • Clomipramine / therapeutic use*
  • Depressive Disorder / blood
  • Depressive Disorder / drug therapy*
  • Depressive Disorder / metabolism*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Panic Disorder / blood
  • Panic Disorder / drug therapy*
  • Panic Disorder / metabolism*
  • Psychiatric Status Rating Scales
  • Serotonin / blood
  • Serotonin / metabolism*
  • Tryptophan / blood
  • Tyrosine / blood


  • Amino Acids
  • Antidepressive Agents, Tricyclic
  • Serotonin
  • Tyrosine
  • Tryptophan
  • Clomipramine