Pharmacological profile of N-(2,6-DIMETHYLPHENYL)-N-(1-methyl-2pyrrolidinylidene)urea, xilobam, a new centrally acting skeletal muscle relaxant.

The pharmacological profile of a new centrally acting skeletal muscle relaxant, xilobam, is described and compared to that of existing skeletal muscle relaxants. The potencyof xilobam, administered intravenously, is approximately ten times that of methocarbamol in the linguomandibular assay in the cat. When evaluated in the strychnin assay in the mouse, the potency of xilobam is approximately seven times that of chlorzoxazone and eleven tomes that of methocarbamol and five times that of metaxalone. In contrast to methocarbamol, xilobam exhibits little or no sedative activity and appears devoid of antianxiety properties. When administered to non-anesthetized dogs, xilobam and other centrally acting muscle relaxants, such as chlorzoxazone and methocarbamol, increased arterial pressure and heart rate. Mydraiasis, vocalization and muscle rigidity were concomitantly observed. These effects appear to be centrally induced. It is concluded that xilobam appears to be a potent centrally acting muscle relaxant which should not be sedating or anxiolytic in man.