Treatment of canine Alopecia X with trilostane

Sixteen Pomeranians and eight miniature poodles presenting with clinical signs of alopecia X, elevated blood concentrations of 17-hydroxyprogesterone post stimulation with adrenocorticotropic hormone and increased urinary cortisol/creatinine ratios were treated with trilostane, a competitive inhibitor of 3beta-hydroxysteroid dehydrogenase. Trilostane was given once or twice daily at a mean dose of 10.85 mg kg(-1) day(-1). Adrenal function was evaluated with a follow-up of 28 months in the Pomeranians and 33 months in the miniature poodles. Treatment with trilostane led to complete hair re-growth in 85% of the Pomeranians and in all of the miniature poodles within 4 to 8 weeks. No adverse events attributed to treatment with trilostane were recognized. The hair re-growth might have been the result of a down-regulation of adrenal steroids and/or of the noncompetitive inhibition of the oestrogen receptors at the hair follicle level.     

Haptoglobin concentrations in dogs undergoing trilostane treatment for hyperadrenocorticism

BACKGROUND: Increased concentrations of haptoglobin (Hp), a moderate acute phase protein, have been demonstrated in dogs with hyperadrenocorticism (HAC). Monitoring serum concentrations of Hp in hyperadrenocorticoid dogs before and after trilostane administration may provide valuable information on the response to therapy. OBJECTIVE: The aim of this study was to measure Hp concentrations in dogs with spontaneously occurring HAC at the time of diagnosis and after treatment with trilostane. METHODS: Serum Hp concentration was measured using an automatic biochemical assay based on Hp-hemoglobin binding and utilizing SB-7 reagent in 12 dogs with spontaneous HAC before and after treatment with trilostane (30 or 60 mg PO q 12-24 h). Post-treatment Hp concentrations were measured at the time the owner reported an improvement in clinical signs. Pretreatment and post-treatment Hp values were compared with reference values and with values from 4 healthy control dogs. RESULTS: Two dogs with HAC had pretreatment Hp values within the reference interval; 10 dogs had moderate (n = 8) or marked (n = 2) increases in Hp concentration. After treatment with trilostane, Hp concentration remained within the reference interval (n = 2), decreased to within the reference interval (n = 3), or remained moderately increased (n = 7; 3-10 g/L). Overall, a significant decrease was observed in Hp concentration after trilostane treatment compared with pretreatment values (P <.005). Both untreated and treated dogs with HAC had significantly higher Hp concentrations (P <.001) when compared with control dogs. CONCLUSIONS: Clinical control of HAC did not closely relate to serum Hp concentration. Further studies are required to assess whether this is because of inadequate control of disease or because a build-up of cortisol precursors or secondary effects of HAC affect Hp concentration.     

Medical management of pituitary-dependent hyperadrenocorticism: mitotane versus trilostane

Pituitary-dependent hyperadrenocorticism is a common endocrine disorder in dogs in the United States. Once a diagnosis is established, a decision must be made whether or not to pursue treatment, and if so, which medication to use. Historically, mitotane (Lysodren, o,p'-DDD, Bristol-Myers Squibb, New York) has been the most commonly used treatment for medical management. Its use is complicated and comes with many potential side effects, making many practitioners wary of its use. Recently, trilostane has been proven to be an effective treatment of pituitary-dependent hyperadrenocorticism and is approved for use in other countries. Treatment with trilostane is somewhat simpler and the incidence of side effects seems to be less when compared with mitotane therapy. Either treatment can be a safe and effective method of treatment for pituitary-dependent hyperadrenocorticism when the practitioner and client are well educated regarding their use and an appropriate monitoring protocol is used.