Double-blind placebo-controlled study of the efficacy of oral terfenadine in the treatment of chronic fatigue syndrome.

Abstract

There is no established treatment for chronic fatigue syndrome (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. Because of anecdotal reports and uncontrolled trials showing antihistamine efficacy in CFS, we evaluated the clinical efficacy of the antihistamine terfenadine (60 mg twice daily) in a placebo-controlled study. Thirty patients with CFS were enrolled in a 2-month, double-blind, placebo-controlled trial of terfenadine. Participants underwent a battery of both immediate- and delayed-type hypersensitivity 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. Twenty-eight patients completed the trial. History of atopy and positive immediate skin test results were prevalent, 73% and 53%, respectively. No evidence for hypoergy or anergy after delayed-type hypersensitivity skin testing was found. No therapeutic benefit from terfenadine could be detected in terms of symptom amelioration, improved physical or social functioning, health perceptions, or mental health. A high incidence of atopy in patients with CFS was confirmed. Although this trial involved a small number of patients, the results suggest that terfenadine is unlikely to be of clinical benefit in treating CFS symptoms.