Purpose: Fatigue and depression typically occur together in cancer patients, suggesting a common etiology, perhaps based on serotonin. This randomized clinical trial tested whether paroxetine, a selective serotonin reuptake inhibitor antidepressant known to modulate brain serotonin, would reduce fatigue in cancer patients and whether any reduction was related to depression.
Patients and methods: Cancer patients undergoing chemotherapy for the first time were assessed for fatigue. Of 704 patients who reported fatigue at their second chemotherapy cycle, 549 patients were randomly assigned to receive either 20 mg of oral paroxetine hydrochloride daily or placebo for 8 weeks. The assessments of fatigue and depression were performed at cycles 3 and 4 of chemotherapy.
Results: A total of 244 patients treated with paroxetine and 235 patients treated with placebo provided assessable data. No difference was detected in fatigue between patient groups. At the end of the study, there was a difference between groups in the mean level of depression (Center for Epidemiologic Studies Depression scores, 12.0 v 14.8, respectively; P <.01).
Conclusion: Paroxetine had no influence on fatigue in patients receiving chemotherapy. A possible explanation is that cancer-related fatigue does not involve a reduction in brain 5-HT levels.