St. John's wort has no effect on pain in polyneuropathy

Tricyclic antidepressants are the mainstay of treatment of painful polyneur opathy but cannot be used in a substantial number of patients. St. John's w ort is a herbal antidepressant, which may act via mechanisms similar to the tricyclics. The aim of this study was to test if St. John's wort would rel ieve painful polyneuropathy. The study design was randomized, double-blind, placebo-controlled and cross-over. Fifty-four patients were assigned to on e of the two treatment sequences. The daily dose of St. John's wort was thr ee tablets each containing 900 mug totalhypericin. During the two treatment periods of 5 weeks duration, patients rated constant pain, lancinating pai n paroxysms, touch-evoked pain acid pain on pressure by use of 0-10 point n umeric rating scales. Forty-seven patients -18 diabetics and 29 non-diabeti cs -completed the study. There was a trend of lower total pain score (sum o f the individual pain scores) on St. John's wort than on placebo (median 14 vs. 15, P = 0.05). None of the individual pain ratings were significantly changed by St. John's wort as compared to placebo (P = 0.09-0.33). Complete , good or moderate pain relief was experienced by nine patients with St. Jo hn's wort and two with placebo (P = 0.07). In conclusion, St. John's wort h as no significant effect on pain in polyneuropathy. (C) 2001 International Association for the Study of Pain. Published by Elsevier Science B.V. All r ights reserved.