Efficacy and dosage titration study of mibolerone for treatment of pseudopregnancy in the bitch.

A controlled, blind-labeled, dose-response field trial was conducted to evaluate the efficacy of mibolerone as a treatment for pseudopregnancy in the bitch. Bitches were treated orally for 5 consecutive days with one of the following dosages of mibolerone: 0.008, 0.016, or 0.025 mg/kg of body weight. Changes in psychologic signs (nesting behavior, mothering inanimate objects, and self-nursing) or physical signs (mammary gland enlargement and secretion of a liquid or milk, ie, galactorrhea) were noted. The period within which the improvement occurred also was noted. There were 63 cases distributed over the 3 dosages--19 at 0.008 mg/kg, 22 at 0.016 mg/kg, and 22 at 0.025 mg/kg. Seventeen bitches given a placebo served as controls. There were significant differences in improvement of clinical signs among the dosages for the combinations of psychologic (P less than 0.001), physical (P less than 0.01), psychologic or physical (P less than 0.001), and psychologic and physical (P less than 0.001). The projected optimal dosages were: 0.016 mg/kg, 0.013 mg/kg, 0.014 mg/kg, and 0.015 mg/kg for the psychologic, physical, psychologic or physical, and psychologic and physical signs, respectively. Of the 3 dosages used, 0.016 mg/kg (for 5 consecutive days) was estimated to be optimal for improvement of the physiologic signs of pseudopregnancy.