Paroxetine and imipramine treatment of depressive patients in a controlled multicentre study with plasma amino acid measurements

Abstract

In a 12-week double-blind study with 36 patients with major depressive episode (DSM-III), paroxetine (Seroxat, Aropax) showed significantly quicker onset of efficacy on the Melancholia Scale, and better tolerance than imipramine. Plasma concentration analyses showed no clear concentration-efficacy correlation in either treatment group. During long-term treatment paroxetine seemed to be superior to imipramine in preventing relapse; both treatments were well tolerated. A significant correlation between baseline plasma tryptophan: large neutral amino acids ratio and final Hamilton Rating Scale for Depression (HRSD) score and a trend towards an inverse correlation between this ratio and percentage reduction in HRSD score were seen in the paroxetine group but not in the imipramine group. In line with previous studies, these results support the hypothesis that paroxetine is an effective and well tolerated antidepressant.

Reversed diurnal variation in depression: associations with a differential antidepressant response, tryptophan:large neutral amino acid ratio and serotonin transporter polymorphisms

“…For instance, Moller et al (1986Moller et al ( , 1990 and Lucca et al (1994) found that lower Trp:LNAA ratios predicted a better response to serontonergic antidepressants. However, the results from other studies have not been completely consistent (Moller et al 1990 ;Nielsen et al 1991;Moller, 1993). In an earlier study of ours (Porter et al 2003), and in this study (Porter et al in press) we have not found that a higher Trp:LNAA ratio predicted a poorer response to antidepressants in general or to serotonergic antidepressants.…”

Effects of dietary tryptophan variations on extracellular serotonin in the dorsal hippocampus of rats

“…Plasma TRP levels have also been shown to predict response to SSRIs. Thus, Lucini et al (1996) suggest that the TRP/LNAA ratio could be of predictive value to antidepressant response, and Nielsen et al (1991) reported a significant correlation between baseline plasma TRP/LNAA ratio and the severity of depression after paroxetine treatment.…”

The efficacy of selective serotonin re-uptake inhibitors in depression: a meta-analysis of studies against tricyclic antidepressants

“…Eight studies were excluded as they did not specify status or included both in-and out-patients. Exceptions to these exclusion criteria were a predominantly in-patient study with only four out-patients (Nielsen et al, 1991) and one which started with in-patients who were subsequently discharged (Lund Laursen et al, 1985); these were both taken to be in-patient studies. We addressed the issue of severity by analysing more and less severe patient groups by taking a median split of severity on the initial HDRS (using the mean of the scores of the two treatment groups for each study) stratified according to use of the 17-and 21-item HDRS (respective medians 24.45 and 26.04).…”