Cushing's Disease and Vetoryl ( Trilostane )

Cushing's Disease is a uncommon condition in older dogs, often mistaken for the aging process itself.  Yet Cushing's disease is treatable, and that treatment can result in a longer, more comfortable life for the dog and its owner


Cushing's Disease is a fairly rare endocrine diseases of dogs

An endocrine disease is a disease affecting one of the many glands that make hormones.  Hormones are chemicals that the body makes to regulate itself.  A more common example of an endocrine disease would be diabetes.  When the pancreas goes bad, not enough insulin is produced, and we have an abnormal hormonal condition known as diabetes.

In the case of Cushing's Syndrome, the hormone in question is cortisol.  Cortisol is a hormone made by the adrenal glands.  In patients with Cushings Syndrome, too much cortisol is produced.  This abnormal condition is also called hyperadrenocorticism, which we call Cushing's Syndrome for short.


Cushing's Disease has many symptoms

Cortisol has many target tissues, and it affects each target tissue in a different way.  Thus, we see many different symptoms in Cushing's Syndrome.

  • increased/excessive water consumption (polydipsia)
  • increased/excessive urination (polyuria)
  • urinary accidents in previously housetrained dogs
  • increased/excessive appetite (polyphagia)
  • sagging, bloated, pot-bellied appearance
  • weight gain or its appearance, due to fat redistribution
  • loss of muscle mass, giving the appearance of weight loss
  • bony, skull-like appearance of head
  • exercise intolerance, lethargy, general or hind-leg weakness
  • excess panting, seeking cool surfaces to rest on
  • symmetrically thinning hair or baldness (alopecia) on torso
  • other coat changes like dullness, dryness
  • slow regrowth of hair after clipping
  • thin, wrinkled, fragile, and/or darkly pigmented skin
  • easily damaged/bruised skin that heals slowly
  • hard, calcified lumps in the skin (calcinosis cutis)
  • susceptibility to infections (especially skin and urinary)
  • diabetes, pancreatitis, seizures

There are also some other signs of Cushing's Syndrome that are only evident on blood tests.  We see elevations in liver enzymes (ALP, ALT, and AST), decreased thyroid levels, a stress leukogram, and high blood pressure.  There are so many different symptoms of Cushing's Disease that it is actually very uncommon for any one patient with Cushing's Disease to show all the symptoms at the same time.


It can be quite difficult to diagnose Cushing's Syndrome

There are four different tests that can be used to test for Cushings' Disease:  the ACTH stimulation test, the Low-Dose Dexamethazone Suppression test, the High-Does Dexamethazone Suppression test, and the Urine Creatinine:Cortisol Ratio test.  Which one to use is a very complex decision, and involves both the art and the science of veterinary medicine.  Which test we use depends on the patient.


Cushing's Syndrome can be treated with a drug called Trilostane

Trilostane, also called Vetoryl, is a newer medication.  It has been around quite a few years now, and had gained wide-spread acceptance as a better choice than the older mitotane.  While the label calls for once-a-day administration, many clinicians are finding that it goes better if given twice a day.  We start Trilostane at the beginning dose, then 14 days later the patient is re-evaluated and another ACTH Stimulation test and a chemistry and/or electrolytes is done.  If all is well, the medication is continued and further ACTH Stimulation test and chemistry and/or electrolytes are done 30 days later, then 90 days later, and then every 3 months after that.  If all is not well on any re-evaluation, dosage changes and follow-up ACTH Stimulation tests are done until the dose is right.


The prognosis for dogs with Cushing's Disease is good with treatment

We expect symptoms of Cushing's to fully resolve over the course of 4-6 months. Excess drinking and urinating abate quickly. It may take several months for hair and coat improvement to be observed. Dogs generally are more comfortable after the disease is under control and may live happily for years. However, Cushing's disease is managed, not cured, and maintaining a dog with Cushing's disease requires vigilance and commitment on the part of the owner, as well as on-going testing.

Left untreated, Cushing's disease will progress. As excess cortisol is immunosuppressive, Cushingoid dogs are prone to various infections. They are also predisposed to developing hypothyroidism, pancreatitis, diabetes, seizures, hypertension, congestive heart failure, blood clots, and liver and kidney failure. It should not go without noting that many of these dogs are at risk of early euthanasia due to incontinence resulting from increased water consumption.  Although the treatment for Cushing's Disease is not without it's own problems, the treatment is much better than the disease, and treatment will prolong the patient's life and improve the quality of life as well.


Cushing's Syndrome is not an inexpensive condition

The last time I checked, which was February of 2017, Trilostane for a 20-pound dog costs a little under $70 per month.  The ACTH testing and chemistry with electrolytes can cost around $225 or more, depending on the patient's size, and we can expect to do about four to six rounds of testing in the first year.  If everything goes perfectly, starting a 20-pound dog on Trilostane and continuing for one year will cost upwards of $1,750 between testing and medications, and that is if everything goes perfectly. It could be more.  For an 80-pound dog, it will cost over $2,000 a year, perhaps well over $2,000.  It is wise to count the costs before beginning treatment.