If your dog missed a trilostane (Vetoryl) dose, you can usually relax: one skipped dose is typically low-stakes. Give it when you remember, but if the next dose is close, skip the missed one and get back on schedule. Never give two doses at once. The bigger risk with trilostane is a double dose, not a missed one. Then call your vet.
That last part surprises most owners, so let's explain why. Quick note up front: trilostane is managed closely by your vet, so consult your veterinarian for advice specific to your dog's medications. This article is general information, not a substitute for that.
Why a Double Dose Is Scarier Than a Missed One
With most medications, the logic is simple: more drug means more effect, and a big overdose means toxicity. Trilostane flips that on its head.
Trilostane's whole job is to lower cortisol. The FDA prescribing information for Vetoryl explains that the drug "selectively inhibits 3β-hydroxysteroid dehydrogenase in the adrenal cortex," which "blocks production of glucocorticoids." In plain English: it dials down the stress hormone that dogs with Cushing's disease make too much of.
So when a dog gets too much trilostane, cortisol does not climb. It crashes. The same FDA label notes that in an overdose, the dog may need "symptomatic treatment of hypoadrenocorticism with corticosteroids, mineralocorticoids and intravenous fluids." That means an overdose is treated like Addison's disease, the opposite of Cushing's, because the drug pushed cortisol too far down.
That is why a missed dose is usually the gentler mistake (cortisol drifts back up on its own) while a double dose is the one that can tip a dog toward an Addisonian crisis, which can be life-threatening. The FDA label is blunt about it: "Hypoadrenocorticism can develop at any dose of VETORYL Capsules."
What to Do If Your Dog Missed a Dose
The FDA label does not actually print a missed-dose rule, so the trusted guidance here comes from VCA Animal Hospitals' trilostane monograph, and the final call always belongs to your vet.
Here is the simple version:
- Remembered soon after? Give the dose with food and continue the normal schedule.
- Almost time for the next dose? Skip the missed one. Resume the regular schedule.
- Never give two doses at once to "catch up." This is the rule that matters most with trilostane.
- Not sure what to do? Call your vet's office and let them decide.
One reason a single missed dose is usually fine: the effect does not last very long. A 2018 review in The Canadian Veterinary Journal notes that "the duration of cortisol suppression after a dose of trilostane is often less than 12 hours." So when a dose is skipped, the dog's own cortisol production simply picks back up. No catch-up dose needed.
| Situation | Usual urgency | What it can lead to |
|---|---|---|
| Missed one dose | Low. Cortisol drifts back up. | Brief return of Cushing's signs (thirst, hunger) |
| Gave a double dose | High. Call your vet. | Cortisol pushed too low, risk of Addisonian crisis |
| Showing GI or weakness signs | Stop and call vet now | Possible over-suppression or crisis |
This is the same "did I already give it?" worry that pet owners face with other meds, like in our guide on what to do when you can't remember if you gave your dog Apoquel. With trilostane, that uncertainty carries more weight, so a reliable system matters. The same double-dose math comes up if you accidentally gave your dog a double dose of carprofen, and the missed-dose-vs-double-dose tension shows up again when a dog misses a furosemide dose for heart failure.
Always Give Trilostane With Food
Trilostane should always be given with food. The Merck Veterinary Manual describes it being given "with food" to help the body absorb it consistently, and MSPCA-Angell puts it plainly: "Trilostane should always be given with food to improve absorption."
Why does this matter for a missed dose? Food changes how much of the drug gets into your dog, so giving it on an empty stomach one day and with a full meal the next makes the results less predictable. Keeping food consistent keeps the dose consistent. If your dog also takes other meds at mealtime, our overview of when to take medication with food covers the general idea. One more thing: trilostane capsules should not be opened or split, per VCA. Give the whole capsule with a meal.
Once a Day or Twice a Day? It Changes Your Risk
This trips owners up. The FDA label says "once daily administration is recommended," but adds that "if clinical signs are not controlled for the full day, twice daily dosing may be needed."
In real life, many vets prescribe it twice a day. The 2023 AAHA Selected Endocrinopathies Guidelines note that "although labeled to be administered once daily, there are several peer-reviewed references that have found that twice-daily use may be preferable." MSPCA-Angell agrees that "twice-a-day treatment is preferred by most clinicians due to the short half-life of the drug."
Here is why that matters to you: a twice-a-day schedule means more chances to lose track and accidentally double up. The "did I give the morning one?" question comes up every single day, and that is exactly the moment a missed-dose mix-up can turn into an accidental double dose.
How Vets Keep an Eye on the Dose
Trilostane is a narrow-margin drug, so dogs on it get monitored. You do not run these tests at home, but knowing what they are helps you understand why your vet wants regular rechecks.
The main tool is the ACTH stimulation test. The FDA label describes it being "conducted 4-6 hours after VETORYL Capsule administration" to check how low cortisol is going. The Canadian Veterinary Journal review calls this test the gold standard for monitoring how a dog responds to treatment. Your vet may also check electrolytes and kidney and liver values.
Cushing's disease itself is mostly a senior-dog problem. The Merck Veterinary Manual notes it "occurs predominantly in middle-aged to older dogs," so many trilostane patients are older dogs already on other meds. That is one more reason consistency counts. For owners juggling several medications, our guide on managing multiple medications without missing doses may help.
Warning Signs: When to Call the Vet Right Away
Because over-suppression is the real danger, you need to know the signs. The FDA label tells owners to "discontinue VETORYL Capsules and contact their veterinarian immediately if signs of intolerance such as vomiting, diarrhea, lethargy, poor/reduced appetite, weakness, or collapse are observed."
In other words, if your dog looks off after a dosing mistake, stopping the drug is the right move, not waiting it out. Call your vet.
Treat these as emergency signs and get to a vet right away:
- Collapse or sudden severe weakness
- Severe or bloody vomiting or diarrhea
- Pale gums
- Profound lethargy or unresponsiveness
The FDA label warns that serious reactions, including "severe depression, hemorrhagic diarrhea, collapse, hypoadrenocortical crisis or adrenal necrosis/rupture may occur, and may result in death." This is rare, but it is the reason trilostane gets more caution than a routine medication. If you ever suspect a double dose or an overdose, VCA advises that you "call your veterinary office immediately."
How Pillo Helps You Never Lose Track
The hardest part of trilostane is not the pharmacology. It is the daily question: did I already give it? Miss a dose and your dog usually drifts back to baseline. But double up out of doubt, and you are in the risky direction.
Pillo's Dependents Management is built for this. You add your dog as a dependent inside your own app, set the trilostane schedule (with-food, and twice daily if your vet prescribed it that way), and Pillo tracks each dose as given. The persistent alarm fires on your phone and keeps nudging until you confirm, so you are never left guessing whether the morning pill happened. That removes the "I think I gave it" guesswork that leads to an accidental double dose. It is the same peace of mind owners want when they can't remember if they took their own medication.
Download Pillo on Google Play and add your dog as a dependent today.
Frequently Asked Questions
My dog missed one trilostane dose. Is that dangerous?
Usually not. A single missed dose of trilostane is typically low-stakes because the drug's cortisol-lowering effect often fades within 12 hours, per a 2018 Canadian Veterinary Journal review. Give the dose when you remember, or skip it if the next one is close. Never give two doses together, and check with your vet if you are unsure.
What happens if I accidentally gave my dog a double dose of trilostane?
A double dose is the higher-risk mistake. Because trilostane lowers cortisol, too much can push it dangerously low toward an Addisonian crisis. The FDA label says overdose may need treatment for hypoadrenocorticism. Call your vet right away, even if your dog seems fine.
Why does trilostane need to be given with food?
Food helps your dog absorb the drug consistently. MSPCA-Angell states that "trilostane should always be given with food to improve absorption." Giving it with a meal one day and on an empty stomach the next makes the dose less predictable, so keep food consistent.
Should my dog take trilostane once or twice a day?
That is your vet's call. The FDA label recommends once daily but allows twice daily if signs are not controlled all day. The 2023 AAHA guidelines note many vets prefer twice-daily dosing because the drug's effect is short. Follow the schedule your vet set, and do not change it on your own.
What are the warning signs that my dog got too much trilostane?
Watch for vomiting, diarrhea, lethargy, poor appetite, weakness, or collapse. The FDA label tells owners to stop the drug and call the vet immediately if these appear. Collapse, severe or bloody vomiting or diarrhea, and pale gums are emergencies. Get to a vet right away.
What happens if my dog skips trilostane for a few days?
Skipping for several days is different from one missed dose. As the drug clears, your dog's cortisol rises again, so the Cushing's signs your vet was managing (heavy thirst, big appetite, frequent urination) can return. It is not usually an emergency, but it is not something to let drift either. Call your vet so they can tell you how to restart and whether your dog needs a recheck.
A Quick Note
This article provides general information about medication management and is not a substitute for professional veterinary advice. Trilostane dosing is managed individually by your vet, and any decision after a missed or double dose is theirs to make. Consult your veterinarian for advice specific to your dog's medications.
