DOUBLE-BLIND PLACEBO-CONTROLLED STUDY OF THE EFFICACY OF ORAL TERFENADINE IN THE TREATMENT OF CHRONIC FATIGUE SYNDROME

Background: There is no established treatment for chronic fatigue synd rome (CFS), an illness characterized by disabling fatigue exacerbated by physical activity. A variety of immunologic abnormalities have been reported, including a high incidence of atopy and hypoergy or anergy. Objective: Because of anecdotal reports and uncontrolled trials showi ng antihistamine efficacy in CFS, we evaluated the clinical efficacy o f the antihistamine terfenadine (60 mg twice daily) in a placebo-contr olled study. Methods: Thirty patients with CFS were enrolled in a 2-mo nth, double-blind, placebo-controlled trial of terfenadine. Participan ts underwent a battery of both immediate- and delayed-type hypersensit ivity skin tests and completed a self-assessment questionnaire used to measure severity of symptoms, physical and social functioning health perceptions, and mental health before each of six biweekly visits. Res ults: Twenty-eight patients completed the trial History of atopy and p ositive immediate skin test results were prevalent, 73% and 53%, respe ctively. No evidence for hypoergy or anergy after. delayed-type hypers ensitivity skin testing was found. No therapeutic benefit from terfena dine could be detected in terms of symptom amelioration, improved phys ical or social functioning, health perceptions, or mental health. A hi gh incidence of atopy in patients with CFS was confirmed. Conclusion: Although this trial involved a small number of patients, the results s uggest that terfenadine is unlikely to be of clinical benefit in treat ing CFS symptoms.