Analgesic effect of o-isobutyrylthiamine disulfide on experimentally induced pain

Abstract

Pain was induced in female Lewis rats by injecting subcutaneously an oily suspension of mycobacteria (adjuvant) into the tail and the pain threshold was measured by pressing the affected portion of the tail two times 24 hr (zero time) and 27 hr (3 hr) after the adjuvant injection. o-Isobutyrylthiamine disulfide, which was administered subcutaneously at a dose of 50 and 100 mg/kg immediately after the determination of the zero-time value, increased significantly the pain threshold at 3 hr as compared with the saline-treated control, while thiamine disulfide and thiamine hydrochlroide had no effect on the adjuvant-induced pain. Another method for estimation of analgecis efficacy of drugs consisted of the intraarticular injection of microcrystalline sodium urate into the hind leg of beagle dogs and measurement of the relative body weight supported by the affected leg. Pain-relief was enhanced by the simultaneous administration of 20 mg/kg of isobutyrylthiamine disulfide by oral or subcutaneous route. At the same dose level, thiamine disulfide was effective only by the subcutaneous route of administration but thiamine hydrochloride was without effect. Isobutyrylthiamine disulfide demonstrated an anti-inflammatory activity against carrageenin-induced edema but had no influence on the development of adjuvant-induced arthritis in rats.