To investigate the effect of an antiviral compound, valacyclovir, on pain and tenderness in patients with the fibromyalgia (FM) syndrome.
Sixty patients were randomized into a double blind, placebo controlled 6 week trial. Primary outcome was pain intensity change (on visual analog scale). Secondary outcome measures were tender points (myalgic score) and Fibromyalgia Impact Questionnaire (FIQ).
Fifty-two patients completed the study. The numbers of dropouts due to adverse events were equal in valacyclovir (2) and placebo (2) groups. The effect of valacyclovir on pain and tenderness and FIQ did not differ from placebo.
Valacyclovir cannot be recommended as a therapy for FM at this point.