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Evaluation of clinical, ultrasonographic, and clinicopathological findings in dogs with pituitary-dependent hypercortisolism and poor trilostane response

Source: PubMed Central Open Access, NCBI / U.S. National Library of Medicine

Journal of Veterinary Internal MedicineLast synced 5/26/2026Status: syncedPMID: 42177638 pmidDOI: 10.1093/jvimsj/aalag096

Abstract Background Trilostane is the treatment of choice for pituitary-dependent hypercortisolism (PDH) in dogs, but predictors of a poor response are unclear. sec1a Hypothesis/Objectives To identify variables associated with a poor response to trilostane in dogs with PDH. sec1b Animals Twenty-three dogs with PDH treated with trilostane. sec1c Methods Retrospective cohort study. Clinical, clinicopathological, endocrine, ultrasonographic, and treatment data were reviewed. Dogs were classified as good responders (GRs) or nonresponders (NRs) based on clinical outcomes after 4-8 months of trilostane treatment. The primary outcome was treatment response. sec1d Results Fifteen dogs were GRs and 8 were NRs. At diagnosis, GRs had lower alanine aminotransferase (ALT) (median [IQR] 182 [70-251] vs 330 [224-578] U/L;= .004), eACTH (14.4 [9.25-29.13] vs 49.2 [34.35-62.35] pg/mL;= .007), and pre-ACTH cortisol (4.28 [3.07-6.52] vs 9.0 [6.57-19.40] μg/dL;= .019) than NRs. Bilateral adrenomegaly was more frequent in NRs (8/8) than in GRs (9/15;= .007). At T1, NRs required more rechecks (median [IQR] 7 [6-7] vs 3 [3-5];< .001) and higher trilostane doses (3.25 [3-5.75] vs 1.22 [0.66-1.60] mg/kg q12h;< .001). After false discovery rate adjustment, ALT, eACTH, alopecia, and bilateral adrenomegaly remained significant (= 0.047 for each). All GRs achieved complete clinical resolution within 4 months of treatment initiation. sec1e Conclusions and clinical importance Higher baseline ALT, eACTH, an

Abstract

Abstract Background Trilostane is the treatment of choice for pituitary-dependent hypercortisolism (PDH) in dogs, but predictors of a poor response are unclear. sec1a Hypothesis/Objectives To identify variables associated with a poor response to trilostane in dogs with PDH. sec1b Animals Twenty-three dogs with PDH treated with trilostane. sec1c Methods Retrospective cohort study. Clinical, clinicopathological, endocrine, ultrasonographic, and treatment data were reviewed. Dogs were classified as good responders (GRs) or nonresponders (NRs) based on clinical outcomes after 4-8 months of trilostane treatment. The primary outcome was treatment response. sec1d Results Fifteen dogs were GRs and 8 were NRs. At diagnosis, GRs had lower alanine aminotransferase (ALT) (median [IQR] 182 [70-251] vs 330 [224-578] U/L;= .004), eACTH (14.4 [9.25-29.13] vs 49.2 [34.35-62.35] pg/mL;= .007), and pre-ACTH cortisol (4.28 [3.07-6.52] vs 9.0 [6.57-19.40] μg/dL;= .019) than NRs. Bilateral adrenomegaly was more frequent in NRs (8/8) than in GRs (9/15;= .007). At T1, NRs required more rechecks (median [IQR] 7 [6-7] vs 3 [3-5];< .001) and higher trilostane doses (3.25 [3-5.75] vs 1.22 [0.66-1.60] mg/kg q12h;< .001). After false discovery rate adjustment, ALT, eACTH, alopecia, and bilateral adrenomegaly remained significant (= 0.047 for each). All GRs achieved complete clinical resolution within 4 months of treatment initiation. sec1e Conclusions and clinical importance Higher baseline ALT, eACTH, and pre-ACTH cortisol, as well as bilateral adrenomegaly, were associated with a poor response to trilostane. A lack of improvement by 4-8 months and the need for higher doses or more rechecks supports early therapeutic reassessment. sec1f

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