Is trilostane safe to continue in an 11-year-old neutered...

This is an excellent and common clinical puzzle, where managing a chronic condition intersects with an acute presentation. My primary concern here is differentiating between an adverse reaction to trilostane (specifically, iatrogenic hypoadrenocorticism or an idiosyncratic GI upset) and an unrelated acute gastrointestinal event.

Given the acute vomiting and diarrhea in an 11-year-old Boxer, coupled with mild hypokalemia and neutrophilia, my immediate recommendation would be to temporarily discontinue trilostane.

Here's my rationale and proposed diagnostic and management plan:

1. Immediate Action & Assessment:
* Stop Trilostane: This is the safest initial step. If the GI signs are due to trilostane over-suppression or an idiosyncratic reaction, discontinuing it allows the adrenal axis to recover and may resolve the clinical signs.
* Assess Hydration & Electrolytes: The mild hypokalemia is concerning, especially with vomiting and diarrhea. Hypokalemia can worsen GI motility and contribute to lethargy.
Baseline Cortisol: This is critical right now. Obtain a baseline cortisol level prior to any steroid administration. If the dog is experiencing iatrogenic hypoadrenocorticism, this value will likely be very low (<2 µg/dL). This will be far more informative than another ACTH stim at this moment, as the goal is to assess the current* adrenal function, not just its response to stimulation.
* Repeat CBC, Chemistry, Urinalysis: A fresh look at the electrolytes (especially Na:K ratio), renal values (BUN/Cr/SDMA), liver enzymes, and a full leukogram will be essential. The neutrophilia could be a stress leukogram, inflammatory, or even related to the ongoing HAC (though less likely if well-controlled).

2. Differential Diagnoses for Acute Vomiting/Diarrhea:
While iatrogenic hypoadrenocorticism is a consideration with trilostane, we must keep a broad differential list for acute GI signs in a geriatric Boxer:
* Iatrogenic Hypoadrenocorticism: The most immediate concern with trilostane. Clinical signs can mimic primary Addison's (lethargy, weakness, GI upset), though the hypokalemia is less typical than hyperkalemia in classic Addison's. However, atypical Addison's (glucocorticoid deficiency only) can present with normal electrolytes.
* Pancreatitis: Common in Boxers, especially with dietary indiscretion.
* Dietary Indiscretion/Acute Gastroenteritis: Still a possibility.
* Acute Kidney Injury/Uremia: Vomiting is a common sign.
* Hepatobiliary Disease: Acute cholecystitis, cholangitis.
* Gastrointestinal Obstruction/Intussusception: Less likely acute onset without prior signs, but possible.
* Inflammatory Bowel Disease (IBD) Flare: If underlying chronic enteropathy.
* Neoplasia: Lymphoma, adenocarcinoma (less likely acute onset as primary cause).
* Toxin/Drug Reaction: Other medications?
* Systemic Illness: Any severe systemic illness can cause secondary GI signs.

3. Diagnostic Workup (Once Stabilized):
* Abdominal Ultrasound: Given the age and acute signs, this is a high-yield diagnostic. I'd be assessing GI wall layering, looking for free fluid, evaluating the pancreas for signs of pancreatitis, and checking for any masses or obstructions.
* Canine Pancreatic Lipase Immunoreactivity (cPLI): If pancreatitis is suspected on ultrasound or clinical signs.
Fecal Floatation/PCR: Rule out common parasites or bacterial overgrowth (e.g., Clostridium perfringens* enterotoxin).

4. Management & Reintroduction of Trilostane:

* Supportive Care: Address dehydration and hypokalemia with intravenous fluids (e.g., LRS with added KCl if needed).
* Antiemetics: Maropitant (Cerenia) at 1 mg/kg PO/SQ q24h is excellent for both vomiting and visceral pain.
* GI Protectants: If ulceration is suspected or there's significant melena, omeprazole at 1 mg/kg PO BID (given 30 min before food).
* Potassium Supplementation: If hypokalemia is significant, add KCl to IV fluids or give oral potassium gluconate.

* Decision on Trilostane Reintroduction:
If Baseline Cortisol is Very Low (<2 µg/dL) and Clinical Signs Resolve: This strongly suggests iatrogenic hypoadrenocorticism. Once stable, reintroduce trilostane at a significantly reduced dose* (e.g., 25-50% of the previous dose) or consider once-daily dosing if currently BID. Recheck an ACTH stim 10-14 days after reintroduction.
If Baseline Cortisol is Normal/Elevated and Clinical Signs Resolve with Supportive Care: This suggests the GI signs were unrelated to trilostane. Once stable, you can likely resume trilostane at the previous dose* (1-2 mg/kg PO BID, starting at the low end as per formulary). Continue to monitor closely.
* If Clinical Signs Persist Despite Stopping Trilostane and Normal Baseline Cortisol: This points to an alternative primary GI issue. Focus diagnostics on the other differentials.

Summary and Confidence:
My initial recommendation is to stop the trilostane immediately and obtain a baseline cortisol along with repeat CBC/Chem/UA. Provide aggressive supportive care for the acute GI signs and hypokalemia. This approach allows us to differentiate between trilostane-induced issues and other common causes of acute gastroenteritis in an older Boxer.

Confidence Level: High confidence in the immediate action (stopping trilostane) and the need for a baseline cortisol. Moderate confidence in the specific next steps, as they will depend on the results of the baseline cortisol and other diagnostics.

I'm here to help interpret those results once you have them.