Lack of hepatotoxicity after long-term administration of cyanamide in rats: a histological and biochemical study. 
An experimental long-term hepatotoxicity study of cyanamide in Sprague-Dawley and Wistar rats has been carried out.  After six months oral administration of cyanamide (2.7 and 25 mg/kg/day) no significant histological changes have been observed in the liver.  Similarly, a one year intraperitoneal administration of 8 and 16 mg/kg/day has not induced any hepatic change.  Specifically, no inclusion bodies in any cyanamide treated rat have been detected.  Moreover, hepatic biochemical parameters have shown no significant impairment of hepatic function at doses used in human therapy (0.5-1 mg/kg).