Dog Cushing's Disease: How to Tell If Your Dog's Medication Is Working

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-14

Key Takeaways

• Treatment for Cushing's disease, typically with trilostane or mitotane, aims to control excessive cortisol production by the adrenal glands, not cure the condition, and requires lifelong management.
• Monitoring treatment efficacy involves tracking specific clinical signs such as reduced water intake and urination, improved appetite, and increased energy, which typically manifest within two to four weeks, though coat and skin changes may take months.
• Crucial to treatment safety are scheduled blood tests to measure cortisol levels, which guide dose adjustments to prevent dangerously low cortisol (hypoadrenocorticism) or insufficient control of hypercortisolism.
• Acute emergencies like collapse, seizures, severe weakness, or repeated vomiting necessitate immediate cessation of medication and emergency veterinary intervention due to the risk of life-threatening hypoadrenocorticism.
• Mild adverse signs such as single vomiting episodes or transient lethargy warrant prompt veterinary consultation for potential dose adjustment, while no improvement after two weeks also requires re-evaluation.
• Concurrent health conditions common in older dogs, such as kidney disease or diabetes, can present with overlapping symptoms and require diagnostic differentiation through physical examination and laboratory testing.

You have probably been watching your dog closely since the diagnosis, and you want to know if the treatment is actually helping. The short answer is that most dogs show clear signs of improvement within two to four weeks of starting medication, but the changes can be gradual and easy to miss. You will need to track specific symptoms, keep up with scheduled blood tests, and stay in contact with your veterinarian. If your dog ever collapses, has a seizure, vomits repeatedly, or becomes extremely weak or unresponsive, stop the medication and go to an emergency vet immediately. Those signs can mean the dose is too high and your dog's cortisol level has dropped dangerously low.

Cushing's disease happens when the adrenal glands produce too much cortisol, a stress hormone that affects nearly every system in the body. The medication your veterinarian prescribed, usually trilostane or mitotane, works by reducing that cortisol production. It does not cure the disease, but it controls it. The goal is to find the lowest dose that keeps your dog comfortable and symptom-free without pushing cortisol too low. That balance is why monitoring matters so much.

Is This an Emergency?

Some changes during treatment are normal and expected. Others are warning signs. Use this table to decide what to do next.

{
 "type": "triage",
 "title": "Urgency triage by severity of signs",
 "tiers": [
  {
   "tier": "danger",
   "label": "Go to emergency vet now",
   "signs": [
    "Collapse, fainting, seizures, severe weakness, repeated vomiting, diarrhea with blood, extreme lethargy where your dog will not stand or respond to you"
   ],
   "action": [
    "Stop giving medication immediately and transport your dog to the nearest emergency clinic",
    "These signs can indicate dangerously low cortisol, which is life-threatening"
   ]
  },
  {
   "tier": "warn",
   "label": "Book a same-day appointment",
   "signs": [
    "Vomiting once or twice, reduced appetite lasting more than 24 hours, unusual tiredness that lasts all day, diarrhea without blood, drinking much less water than usual"
   ],
   "action": [
    "Call your veterinarian the same morning",
    "They may advise a blood test to check cortisol levels before your dog takes the next dose",
    "Do not give another dose until you have spoken to them"
   ]
  },
  {
   "tier": "safe",
   "label": "Watch at home for a defined period",
   "signs": [
    "No improvement in drinking, urination, or appetite after two weeks of treatment, mild increase in thirst, occasional soft stool, normal energy but still panting more than usual"
   ],
   "action": [
    "Keep a daily log of water intake, urination frequency, and appetite",
    "Continue medication as prescribed and report your observations at the scheduled recheck appointment"
   ]
  }
 ]
}

If you are ever unsure, call your veterinary clinic. They would rather hear from you than wait until a problem becomes serious.

What Is Most Likely Going On

Your dog has started a medication that changes hormone levels in the body. That process takes time. The drug does not work like a pain reliever that gives relief within an hour. Instead, it gradually lowers cortisol production over days and weeks. Most dogs begin to show measurable improvement in drinking and urination within the first one to two weeks. Changes in coat, skin, and energy level often take longer, sometimes six to eight weeks or more.

The most common medication, trilostane, is given once or twice daily. Your veterinarian will have scheduled a follow-up blood test, usually about 10 to 14 days after starting treatment. That test measures cortisol before the next dose is due. The result tells your veterinarian whether the dose is right, too high, or too low. Do not skip this test. It is the single most reliable way to know if the medication is working safely.

What Else Could Be Going On

Not every change during treatment is caused by the medication itself. Some signs can come from the disease still being active. Others can come from a separate condition entirely. Cushing's disease is common in older dogs, and older dogs often have more than one health problem at once.

For example, increased thirst and urination can also be caused by kidney disease, diabetes, or a urinary tract infection. The International Renal Interest Society staging guidelines describe how chronic kidney disease is diagnosed and monitored, and it is worth remembering that kidney problems can exist alongside Cushing's disease. If your dog's drinking does not improve after several weeks of treatment, your veterinarian may want to run additional tests to rule out these other causes.

Similarly, a poor appetite or vomiting could be a sign that the dose is too high, but it could also be an unrelated stomach issue. The MSD Veterinary Manual Pet Owner Version explains that many conditions share overlapping signs, which is why a physical examination and blood work are necessary to sort out the cause. Never assume a symptom is just part of the disease or just a side effect. Let your veterinarian decide.

What Improvement Should Look Like

The first change most owners notice is in water consumption. Your dog may stop camping out by the water bowl and may stop waking you at night to go out. You can measure this by filling the bowl to the same level each morning and seeing how much is gone by evening. A clear drop over the first two weeks is a good sign.

Next comes appetite. Many dogs with Cushing's disease act constantly hungry, begging and scavenging for food. That hunger usually eases as cortisol levels come down. Your dog should still eat normally at meal times, but the frantic, never-satisfied behavior should fade.

Energy and panting improve more slowly. Dogs that were reluctant to go on walks may gradually regain interest. Panting that happened at rest, without heat or exercise, should become less frequent. Skin and coat changes, such as thinning fur, dark patches, or a pot-bellied appearance, take the longest to resolve and may never fully reverse. The AAHA Senior Care Guidelines for Dogs and Cats emphasize that chronic disease monitoring in older pets should focus on quality of life, also lab values. Ask yourself whether your dog seems more comfortable, more like their old self, and more engaged with the family.

When to Call Your Veterinarian

Call your veterinarian if you see any of the same-day signs listed above, or if you notice no improvement after two weeks. Call before giving the next dose if your dog vomits, stops eating, or seems unusually tired. These can be early signs that cortisol has dropped too low, and your veterinarian may want to adjust the dose before continuing.

Your veterinarian will also set a schedule for follow-up blood tests. These tests are not optional extras. They are the only way to confirm that the medication is working at a safe level. The AVMA pet owner resources advise pet owners to maintain open communication with their veterinary team and to ask questions whenever something seems unclear. Write down what you observe at home, bring that log to every appointment, and trust your instincts. You know your dog better than anyone, and your observations are a vital part of successful treatment.

What You Can Do at Home Right Now

Start by keeping a daily log. You do not need special training to do this, and it gives your veterinarian the single most useful tool for adjusting treatment. Write down the date, the time you gave the medication, and anything you observe about your dog that day.

Do not change the dose on your own. Do not skip doses because your dog seems better. Do not give extra doses because your dog seems worse. Cushing's medication works on a narrow balance, and the dose must be matched to your dog's individual response through testing. Your veterinarian determines that dose, and only your veterinarian should change it.

Do not give any human medication for Cushing's disease. Some human drugs can cause severe harm in dogs. If you are unsure whether a medication is safe, call your veterinarian before giving anything.

Do not stop the medication abruptly if you suspect a problem. Some withdrawal effects can occur, and your veterinarian needs to guide any change. If your dog collapses, has seizures, or cannot stand, that is an emergency. Seek in-person emergency care immediately.

What to Write Down Before You Call

Your observations are the most valuable information you can bring. Before contacting your veterinarian, gather these specific details:

• Water intake. Measure how much water you put in the bowl each morning, then measure what is left at night. Do this for two or three days. A rough estimate is fine, but numbers help.
• Urination frequency. Count how many times your dog urinates in a 24-hour period. Note any accidents in the house, especially at night.
• Appetite. Note whether your dog finishes meals, begs constantly, or has lost interest in food.
• Energy level. Describe your dog's activity in plain terms. Does your dog join you for walks, or lie flat and refuse to move?
• Skin and coat. Note any hair loss, thinning, redness, or sores. Take a photo each week in the same spot and same lighting.
• Body condition. Run your hands along your dog's ribs and belly weekly. Note whether the belly looks more rounded or the ribs feel more prominent.
• Any vomiting, diarrhea, or unusual behavior. Write down the time and how many times it happened.

Bring this log to every appointment. It helps your veterinarian see patterns that a single exam cannot reveal.

The Monitoring Checklist

Use this checklist at home to track progress. Print it, keep it on the fridge, and fill it in weekly.

Interpreting Common Symptoms

Not every change means the medication is failing. Here is how to read what you see.

Improvement in water intake and urination. This is usually the first sign the medication is working. Within two to four weeks, most dogs drink and urinate less. If your dog still drinks excessively after a month, the dose may need adjustment.

Improvement in appetite. A dog that stops begging and eats normal meals is responding well. A dog that loses interest in food entirely may be getting too much medication.

Energy and activity. Gradual improvement over several weeks is normal. Sudden lethargy, weakness, or collapse is not. That requires immediate veterinary attention.

Skin and coat. Hair regrowth takes time, often two to three months. Skin sores may heal slowly. Do not expect overnight changes.

Belly size. The pot-bellied appearance may take months to reduce. It may never fully resolve in some dogs.

Vomiting, diarrhea, or poor appetite. These can be signs of under-dosing or over-dosing. They can also be unrelated stomach upset. Call your veterinarian for guidance. Do not wait several days.

When an Online Vet Can Help, and When It Cannot

Some situations in this article require hands-on care and must not be handled remotely. If your dog collapses, has seizures, cannot stand, vomits repeatedly, has bloody diarrhea, or shows signs of severe weakness, seek in-person emergency care immediately. No remote consultation can replace that.

A remote consultation is genuinely useful for early or mild presentations, a recheck on a known problem, a question about whether a sign warrants a visit, a medication side effect question, or a follow-up on a chronic condition. If your dog has been stable for months and you are wondering whether a small change matters, a video call can help you decide.

A remote veterinarian can take a history, look at visible signs on video, advise you, and in many states prescribe. But a remote veterinarian cannot palpate the abdomen, listen to the chest, take a temperature, run bloodwork, or image anything. Those limitations matter for Cushing's monitoring, because dose adjustments depend on blood tests.

Prescribing rules differ by state. A veterinarian may require an in-person examination before prescribing or refilling medication. Ask about this when you book a remote visit.

What a Veterinary Visit Usually Involves

Your veterinarian will ask about the signs you have logged. They will examine your dog, feel the abdomen, check the skin and coat, and listen to the heart and lungs. They will likely recommend bloodwork to measure cortisol levels and to check liver and kidney function. The timing of the blood test matters. It is usually taken a few hours after the morning medication dose, so follow your veterinarian's instructions about when to give the medication on test day.

The cost of monitoring varies widely by region and clinic. A basic recheck with bloodwork might range from $100 to $300. A full diagnostic workup with multiple tests can range from $300 to $800 or more. These are general ranges only, not quotes. Ask your clinic for an estimate before any testing.

The frequency of visits depends on your dog's response. Early on, rechecks may happen every two to four weeks. Once stable, visits may be every three to six months. The American Animal Hospital Association senior care guidelines emphasize regular monitoring for chronic conditions in older pets. Your veterinarian will tailor the schedule to your dog.

What to Expect Long Term

Cushing's disease is usually managed, not cured. Most dogs need medication for life. The goal is to control signs while avoiding side effects. Some dogs do very well for years. Others need frequent dose adjustments. Your job is to keep the log, watch for changes, and stay in contact with your veterinarian.

The MSD Veterinary Manual explains that treatment aims to reduce cortisol production to a safe level without eliminating it entirely. That balance is why monitoring matters so much.

If you are ever unsure whether a sign is normal, call your veterinarian. A quick phone call is always better than waiting and worrying. Your observations, combined with your veterinarian's testing, give your dog the best chance at a stable and comfortable life.

Common Mistakes Owners Make With Cushing's Treatment

Stopping medication too soon. Trilostane and mitotane do not cure Cushing's disease. They control it. Many dogs show clear improvement within two to four weeks, but some need dose adjustments over several months. Stopping because your dog seems better can allow symptoms to return quickly. Always finish the full course your veterinarian prescribed and attend every recheck.

Judging success by one symptom. Drinking less is often the first sign the drug is working, but it is not the only sign. Your dog may still have a ravenous appetite or thin skin for weeks. Improvement is gradual and uneven. Track all symptoms, also the one that bothers you most.

Changing the dose on your own. Cushing's drugs have a narrow safety window. Too little means no effect. Too much can cause dangerous low cortisol, a condition called hypoadrenocorticism. Only your veterinarian can interpret blood test results and adjust the dose safely. Never split, double, or skip pills based on how your dog looks.

Missing the recheck blood tests. These tests are not optional. They measure cortisol levels to confirm the drug is working without overshooting. Skipping them leaves you guessing. Most veterinarians recommend testing at two to four weeks after starting or changing a dose, then every three to six months once stable.

Confusing side effects with the disease. Vomiting, diarrhea, weakness, or collapse can mean the dose is too high. These are not normal Cushing's symptoms. They require an urgent call to your veterinarian, not a wait-and-see approach.

How to Reduce the Chance of Problems

Give medication at the same time each day, with food if your veterinarian recommends it. Keep a simple calendar or phone reminder. Store pills in their original container, away from heat and moisture.

Keep a symptom diary. Write down how much water your dog drinks in 24 hours, how often they urinate, and whether accidents happen indoors. Note appetite, energy level, and any skin or coat changes. Bring this diary to every appointment. It gives your veterinarian information that blood tests alone cannot provide.

Follow the senior care guidance from the American Animal Hospital Association for regular wellness checks. Cushing's disease often appears alongside other age-related conditions like arthritis, dental disease, or kidney issues. Routine exams catch these early.

What Ongoing Management Usually Looks Like

Most dogs on Cushing's medication improve noticeably within two to four weeks. The first change is usually reduced thirst and urination. Appetite may take longer to normalize. Skin and coat improvements can take two to three months. Hair regrowth, especially on the trunk and tail, is often the slowest sign to resolve.

Once your dog is stable, expect rechecks every three to six months. These visits include a physical exam, blood work, and a review of your symptom diary. The MSD Veterinary Manual notes that lifelong monitoring is part of managing this condition. Many dogs live comfortably for years with proper treatment.

Some dogs need dose changes over time. The disease can progress, or your dog's metabolism can shift with age. Do not be alarmed if your veterinarian adjusts the dose at a recheck. That is normal management, not a failure.

Quality of life is the real measure of success. A dog who drinks normally, sleeps well, has energy for walks, and eats a healthy amount is doing well, even if some cosmetic signs remain. Focus on function, not perfection.

Frequently Asked Questions

How long until I see improvement in my dog? Most dogs show reduced thirst and urination within one to two weeks of starting trilostane. Appetite changes may take three to four weeks. Skin and hair coat improvements are slower, often taking two to three months. If you see no change at all after four weeks, call your veterinarian. The dose may need adjustment, or additional testing may be needed.

Can my dog ever stop taking Cushing's medication? No. Cushing's disease is a lifelong condition. Medication controls symptoms but does not cure the underlying problem. Stopping treatment usually causes symptoms to return within days to weeks. Some dogs with pituitary tumors eventually need different medications or radiation, but that decision is made by your veterinarian based on imaging and blood work.

What happens if I miss a dose? Give the missed dose as soon as you remember, unless it is almost time for the next dose. In that case, skip the missed dose and continue the regular schedule. Never give two doses at once. Call your veterinarian if you miss more than one dose or if you are unsure what to do.

My dog is vomiting after starting the medication. Is this normal? No. Vomiting, diarrhea, weakness, lethargy, or collapse can mean the dose is too high and cortisol levels have dropped too low. This is a potentially serious situation. Call your veterinarian immediately. Do not give another dose until you have spoken with them. If your dog collapses or cannot stand, seek emergency care right away.

How much does monitoring cost? Costs vary widely by region and clinic. Initial blood tests after starting treatment often range from $100 to $300. Routine rechecks every three to six months may be similar. Your clinic can give you an estimate before testing. Some pet insurance plans cover Cushing's treatment and monitoring. Ask your provider about coverage.

Can I use an online vet for dose adjustments? Online veterinarians can answer general questions and review symptom logs, but they cannot perform the blood tests needed to adjust Cushing's medication safely. Dose changes require current cortisol measurements. Use online services for routine questions, but keep in-person visits for blood work and physical exams. The American Veterinary Medical Association recommends building a relationship with a veterinarian who can examine your dog directly.

Related Clinical & Scientific Guides

• How to Help Your Senior Cat with Mobility Issues: Tips and Products
• How to Prepare Your Cat for a Vet Visit for Kidney Disease
• What Blood Tests Does My Senior Dog Need and What Do They Cost?

References and Further Reading

• AAHA Senior Care Guidelines for Dogs and Cats
• International Renal Interest Society Staging Guidelines
• AVMA Pet Owner Resources
• MSD Veterinary Manual Pet Owner Version
• AAHA Pet Owner Resources

Related Articles

• How to Tell If Your Dog's Increased Thirst Is a Sign of Cushing's Disease
• How to Tell If Your Dog's Cough Is Heart Disease or Something Else
• Dog Kidney Disease: How to Tell If Your Dog Is Dehydrated
• How to Tell If Your Senior Dog's Bad Breath Is a Sign of Kidney Disease
• Dog Cushing's Disease: What to Expect from Diagnosis to Daily Management

This article is general educational information for pet owners. It is not a substitute for veterinary diagnosis, examination, or treatment. If your pet is showing severe or rapidly worsening signs, contact an emergency veterinary hospital immediately.