Unintended Ingestion of Trilostane in Dogs

Source

Summers L, Schuett J, Stern L. Clinical findings, treatment recommendations, and outcome in dogs following ingestion of a single unintended dose of trilostane: 403 cases (2008-2023). J Vet Emerg Crit Care (San Antonio). 2026;36(3):351-356. doi:10.1111/vec.70112

Trilostane is an adrenocortical suppressant labeled for treatment of canine hyperadrenocorticism. Although this drug is generally well tolerated, mild and self-limiting adverse effects (eg, lethargy, vomiting, diarrhea, mild electrolyte imbalances) may occur.

This retrospective study sought to characterize the clinical signs, treatment, and outcomes in dogs following ingestion of a single, unintended dose of trilostane. Cases (n = 403) were identified from an animal poison control center database spanning ≈15 years. Of these cases, 248 dogs (61.5%) ingested trilostane from another dog’s prescription, 147 (36.5%) voluntarily ingested an excess dose of their own prescription, and 6 (1.5%) were inadvertently overdosed by their owner. Active clinical signs were reported in 41 dogs (10.2%), most commonly vomiting, lethargy, and diarrhea. Median onset of clinical signs was 2.5 hours (range, 0.25-72 hours), and median dose ingested by dogs with clinical signs was 10 mg/kg (range, 1.6-245 mg/kg). The median dose ingested in the remaining 362 dogs was 2.94 mg/kg (range, 0.2-202.5 mg/kg).

Clinicopathologic data available for 9 dogs demonstrated mild hyperkalemia, mild hyponatremia, monocytosis, and hypercalcemia. Four dogs received veterinary care, including 2 as outpatients and 1 that was hospitalized for 24 hours. The fourth dog was euthanized after cardiopulmonary arrest; however, this dog had comorbidities that included an unspecified heart condition.

The authors concluded that dogs that ingest a single, unintended dose of trilostane are likely to develop mild, self-limiting clinical signs; however, the need for extensive hospitalization or aggressive medical care is unlikely, even with a high single dose.