Stanozolol appears to offer less hepatic stress than an equivalent dose of Dianabol (methandrostenolone). Studies giving 12mg of stanozolol per day for 27 weeks failed to demonstrate clinically-significant changes in markers of liver function, including serum aspartate amino-transferase, alanine amino-transferase, gamma-glutamyltransferase, bilirubin, and alkaline phosphatase. 621 Relative hepatotoxicity increases as the dosage escalates, so hepatic dysfunction should still be a concern. In rare instances, high doses (alone or in combination with other steroids) have been implicated in cases of serious life-threatening hepatotoxicity in bodybuilders. Injectable stanozolol has also been implicated in severe hepatotoxicity in an otherwise healthy bodybuilder, 622 and should not be used as an alternative medication when liver toxicity precludes oral stanozolol use.
The 30 mg/day dose was poorly tolerated and resulted in the clinical deterioration and euthanasia of four of the six cats in that group. Two of the cats showed signs of anemia, thrombocytopenia and severe clinical deterioration. One had been on the drug for 34 days, the other for 9 weeks. The drug was discontinued in a third cat treated with 30 mg/day while it received supportive care. It was euthanized on day 55 after becoming anorexic. This cat had anemia (HCT %) and red blood cell agglutination. Necropsy showed inflammation of the muscular layer of the stomach and a small erosion in the stomach. A fourth cat treated with 30 mg/day was euthanized after several days of anorexia when the decision was made to discontinue dosing in this group. All 30 mg/day cats that died had generalized lymphadenopathy. Necropsies revealed reactive lymph nodes and varying degrees of inflammation throughout the body. The remaining two cats in the 30 mg/day group were taken off Felimazole tablets at week 9 and fully recovered.
Dienogest was synthesized in 1979 in Jena , Germany under the leadership of Kurt Ponsold, was initially referred to as STS-557 .   It was found that its potency was 10 times that of levonorgestrel .  The first product on the market to contain dienogest was a combined oral contraceptive pill (with ethinylestradiol), Valette, introduced in 1995 and made by Jenapharm .  In 2007, dienogest was introduced as Dinagest in Japan for the treatment of endometriosis, and it was subsequently marketed for this indication as Visanne in Europe and Australia in December 2009 and April 2010, respectively.  Qlaira was introduced in Europe in 2009 and Natazia was introduced in the United States in 2010.