Tryptophan depletion in chronic fatigue syndrome, a pilot cross-over study

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) is still an enigmatic disorder. CFS can be regarded as a complex disorder with tremendous impact on lives of CFS-patients. Full recovery without treatment is rare. A somatic explanation for the fatigue is lacking. There is clinical and experimental evidence implicating enhanced serotonergic neurotransmission in CFS.

Genetic studies and imaging studies support the hypothesis of upregulated serotonin system in CFS. In line with the hypothesis of an increased serotonergic state in CFS, we performed a randomised clinical trial investigated the effect of 5-HT3 receptor antagonism in CFS. No benefit was found of the 5-HT3 receptor antagonist ondansetron compared to placebo.To further investigate the involvement of serotonin in CFS we performed a placebo controlled cross over pilot study investigating the effect of Acute Tryptophan Depletion.

FINDINGS: Five female CFS-patients who met the US Center for Disease Control and Prevention criteria for CFS were recruited. There were two test days, one week apart. Each participant received placebo and ATD. To evaluate the efficacy of the ATD procedure tryptophan and the large neutral amino acids were measured. The outcome measures were fatigue severity, concentration and mood states. ATD resulted in a significant plasma tryptophan to large neutral amino acid ratio reduction of 96%. There were no significant differences in fatigue-, depression and concentration between the placebo- and ATD condition.

CONCLUSIONS: These first five CFS-patients did not respond to the ATD procedure. However, a much larger sample size is needed to draw final conclusions on the hypothesis of an increased serotonergic state in the pathophysiology of CFS.

TRIAL REGISTRATION: ISRCTN07518149.

 

Source: The GK, Verkes RJ, Fekkes D, Bleijenberg G, van der Meer JW, Buitelaar JK. Tryptophan depletion in chronic fatigue syndrome, a pilot cross-over study. BMC Res Notes. 2014 Sep 16;7:650. doi: 10.1186/1756-0500-7-650. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4176591/ (Full article)

 

The effect of ondansetron, a 5-HT3 receptor antagonist, in chronic fatigue syndrome: a randomized controlled trial

Abstract:

BACKGROUND: Accumulating data support the involvement of the serotonin (5-hydroxytryptamine [5-HT]) system in the pathophysiology of chronic fatigue syndrome. Neuropharmacologic studies point to a hyperactive 5-HT system, and open-label treatment studies with 5-HT(3) receptor antagonists have shown promising results. In this randomized controlled clinical trial, the effect of ondansetron, a 5-HT(3) receptor antagonist, was assessed on fatigue severity and functional impairment in adult patients with chronic fatigue syndrome.

METHOD: A randomized, placebo-controlled, double-blind clinical trial was conducted at Radboud University Nijmegen Medical Centre, The Netherlands. Sixty-seven adult patients who fulfilled the US Centers for Disease Control and Prevention (CDC) criteria for chronic fatigue syndrome and who were free from current psychiatric comorbidity participated in the clinical trial. Participants received either ondansetron 16 mg per day or placebo for 10 weeks. The primary outcome variables were fatigue severity (Checklist Individual Strength fatigue severity subscale [CIS-fatigue]) and functional impairment (Sickness Impact Profile-8 [SIP-8]). The effect of ondansetron was assessed by analysis of covariance. Data were analyzed on an intention-to-treat basis. All patients were recruited between June 2003 and March 2006.

RESULTS: Thirty-three patients were allocated to the ondansetron condition, 34 to the placebo condition. The 2 groups were well matched in terms of age, sex, fatigue severity, functional impairment, and CDC symptoms. Analysis of covariance showed no significant differences between the ondansetron- and placebo-treated groups during the 10-week treatment period in fatigue severity and functional impairment.

CONCLUSIONS: This clinical trial demonstrates no benefit of ondansetron compared to placebo in the treatment of chronic fatigue syndrome.

TRIAL REGISTRATION: www.trialregister.nl: ISRCTN02536681.

©Copyright 2010 Physicians Postgraduate Press, Inc.

 

Source: The GK, Bleijenberg G, Buitelaar JK, van der Meer JW. The effect of ondansetron, a 5-HT3 receptor antagonist, in chronic fatigue syndrome: a randomized controlled trial. J Clin Psychiatry. 2010 May;71(5):528-33. doi: 10.4088/JCP.08m04719whi. Epub 2010 Jan 26. https://www.ncbi.nlm.nih.gov/pubmed/20122367

 

Treatment of chronic fatigue syndrome with 5-HT3 receptor antagonists–preliminary results

Abstract:

OBJECTIVE: The serotonin system presumably is involved in the pathogenesis of chronic fatigue syndrome (CFS). Results from a few studies led to the hypothesis of a “postsynaptic hyperresponsiveness” in CFS. Therefore we intended to evaluate the efficacy of 5-HT3 receptor antagonists in the treatment of CFS.

PATIENTS AND METHODS: 2 patient groups (10 patients each; CFS according to the CDC classification criteria) received either oral tropisetron (5 mg once daily) or oral ondansetron (2 x 8 mg daily), open-labelled. Treatment duration was 15 days. Treatment response was evaluated by visual analog scales (VAS) for fatigue and capability.

RESULTS: 19 patients finished their respective study. In the tropisetron group 6/9 (VAS fatigue) and 7/9 (VAS capability) patients documented benefit, 8/10 rsp. 8/10 patients in the ondansetron group. The score changes (VAS before and after treatment) in case of response were more pronounced in the tropisetron group. The frequency of concomitant symptoms did not differ significantly in the treatment groups. The overall analysis of both studies showed a remarkable improvement (> or = 35%) of approximately one third of the patients in both VAS. Treatment was well tolerated.

CONCLUSION: Our preliminary results encourage to perform placebo-controlled, double-blind studies to further evaluate the efficacy of 5-HT3 receptor antagonists in the treatment of CFS.

Source: Späth M, Welzel D, Färber L. Treatment of chronic fatigue syndrome with 5-HT3 receptor antagonists–preliminary results. Scand J Rheumatol Suppl. 2000;113:72-7. http://www.ncbi.nlm.nih.gov/pubmed/11028837