Medical treatment of pituitary-dependent hyperadrenocorticism. Mitotane.

Mitotane (o,p'-DDD; Lysodren) is the drug most commonly used to treat dogs with pituitary-dependent hyperadrenocorticism. Although variations of the original protocol, suggested more than 20 years ago, have been reported, most clinicians still use an initial loading dose of mitotane followed by a weekly maintenance dose. Although a gratifying response to treatment is seen in most dogs, some dogs are neither easy nor straightforward to treat and present the practitioner with one or more therapeutic challenges, including failure to respond adequately, development of adverse effects, or development of relapse during treatment. Nevertheless, with careful management and follow-up, such problems can be overcome and a successful outcome achieved in most cases.