Cushing’s disease — pituitary-dependent hyperadrenocorticism — is the most common cause of spontaneous hypercortisolism in dogs, and trilostane (Vetoryl) is now the FDA-approved treatment of choice. Managing a dog on trilostane well is a monitoring-intensive undertaking: the drug requires post-ACTH stimulation cortisol assessment at 10 days post-initiation, 4 weeks, and 12 weeks, with dose adjustments at each step based on both laboratory results and — critically — owner-reported clinical signs. AAHA guidelines emphasise that trilostane monitoring “utilises a combination of pet owner reports of clinical signs, physical examination, and laboratory testing.” The owner’s observations between appointments are not supplementary — they are a primary data source that drives clinical decisions.
Why Cushing’s follow-up hinges on owner-reported signs
Trilostane’s mechanism — inhibiting adrenal steroid synthesis — means both over-treatment and under-treatment carry significant clinical risks. Under-treated dogs continue to suffer the consequences of hypercortisolism: polydipsia, polyphagia, muscle wasting, pot-belly appearance, skin and coat changes, and susceptibility to infection. Over-treated dogs can develop iatrogenic hypoadrenocorticism (Addison’s-like syndrome), which is potentially life-threatening and presents as lethargy, reduced appetite, vomiting, weakness, and collapse.
The overlap between “Cushing’s dog doing well on trilostane” and “Cushing’s dog developing Addison’s from over-treatment” can be subtle in early stages. An owner who is specifically asked — “has he been more lethargic than usual? Any vomiting? Still eating enthusiastically?” — provides the clinical context that determines whether the laboratory result indicates good control or early adrenal insufficiency. Relying on the ACTH stimulation test alone, without owner context, is insufficient.
Research has also shown that dogs with inadequate follow-up and monitoring have significantly higher rates of disease relapse and severe illness from poorly regulated hypercortisolism. The median survival time for dogs with pituitary-dependent Cushing’s treated twice daily with trilostane was 998 days in one study — nearly three years — which is an excellent outcome that requires consistent monitoring to achieve.
The Cushing’s disease follow-up timeline
| Timepoint | What to check | Red flags |
|---|---|---|
| 10 days post-initiation | ACTH stimulation test (labelled protocol), owner-reported clinical signs, any adverse effects from trilostane (lethargy, reduced appetite, vomiting, weakness) | Post-ACTH cortisol ≤ 1.45 µg/dL with clinical signs of hypoadrenocorticism — stop trilostane immediately, contact vet; severe lethargy, vomiting, weakness |
| 4 weeks | ACTH stimulation test, dose adjustment based on results and clinical signs, improvement in PU/PD, polyphagia, panting, pot-belly? | No improvement in clinical signs despite apparently controlled cortisol levels — consider twice-daily dosing, absorption issues, or alternative diagnoses |
| 12 weeks | Full reassessment, dose now established for stable monitoring, clinical signs well controlled | Signs resurfacing after previous control — dose may need increasing; concurrent disease emerging |
| Every 3–6 months (stable) | ACTH stimulation test or pre-pill cortisol, owner-reported signs, weight, coat quality, blood pressure (hypertension present in 50–70% of Cushing’s dogs) | Cortisol above target with resurgent clinical signs — dose increase needed; new hypertension-related signs |
What to ask owners during Cushing’s follow-up
- Has [dog name]‘s excessive drinking and urination improved since starting trilostane?
- Has the ravenous appetite reduced at all?
- Has he been panting less, particularly at night?
- Is his energy level improving, or does he seem more lethargic than before?
- Has he had any vomiting or reduced appetite since starting the medication?
- Does he seem weak — reluctant to go up stairs, wobbly on his legs?
- Is his coat or skin showing any improvement — less oiliness, improved hair regrowth?
- Have you been giving the trilostane consistently with food at the same time each day?
- Do you have your ACTH stimulation test appointment booked?
- Are there any other changes you’ve noticed that don’t fit neatly into any of these categories?
Common Cushing’s follow-up mistakes clinics make
Not including owner-reported signs in dose decisions. A post-ACTH cortisol in the “acceptable” range does not automatically mean the dog is well controlled. If the owner reports persistent polydipsia, polyphagia, and panting, the dose may be inadequate despite a borderline-acceptable cortisol result. Conversely, a mildly elevated cortisol result with an owner reporting excellent clinical control may not require immediate dose escalation. Owner reports are a co-equal data source with the laboratory.
Missing early hypoadrenocorticism signals. The transition from well-controlled Cushing’s to over-treatment-induced hypoadrenocorticism can be gradual — lethargy appearing first, then reduced appetite, then vomiting. A follow-up call that asks specifically about energy levels and appetite at every touchpoint catches this pattern before it reaches clinical crisis.
Not addressing blood pressure monitoring. Hypertension is present in 50–70% of dogs with hyperadrenocorticism. Blood pressure measurement should be part of every Cushing’s recheck, and owners should be aware of hypertension-related signs (neurological symptoms, vision changes, acute blindness). This is frequently omitted from the discharge conversation.
How to automate Cushing’s follow-up without adding to your team’s workload
Nidana Loop schedules owner-reported sign checks between the formal ACTH stimulation test appointments — a 5-day check after initiation to confirm no early adverse effects, and a monthly call for stable patients to monitor owner-observed clinical response. These calls ask about the specific signs that matter for Cushing’s management: PU/PD, appetite, panting, energy, and any new adverse signs. The clinic receives summaries and flags for cases where the owner reports deterioration or adverse effects between appointments.
See how Loop handles Cushing’s disease follow-up calls → Book a 20-minute demo
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