Chronic fatigue syndrome has been associated with decreased function of the hypothalamic-pituitary-adrenal axis. Although neurally mediated hypotension occurs more frequently in patients with chronic fatigue syndrome than in controls, attempts to alleviate symptoms by administration of hydrocortisone or fludrocortisone have not been successful. The purpose of this study was to investigate the effect of combination therapy (5 mg/d of hydrocortisone and 50 μg/d of 9-alfa-fludrocortisone) on fatigue and well-being in chronic fatigue syndrome.

We performed a 6-month, randomized, placebo-controlled, double-blind, crossover study in 100 patients who fulfilled the 1994 Centers for Disease Control and Prevention criteria for chronic fatigue syndrome. Between-group differences (placebo minus treatment) were calculated on a 10-point visual analog scale.

Eighty patients completed the 3 months of placebo and 3 months of active treatment in a double-blind fashion. There were no differences between treatment and placebo in patient-reported fatigue (mean difference, 0.1; 95% confidence interval [CI]: −0.3 to 0.6) or well-being (mean difference, −0.4; 95% CI: −1.0 to 0.1). There were also no between-group differences in fatigue measured with the Abbreviated Fatigue Questionnaire, the Short Form-36 Mental or Physical Factor scores, or in the Hospital Anxiety and Depression Scale.

Low-dose combination therapy of hydrocortisone and fludrocortisone was not effective in patients with chronic fatigue syndrome.