Cushing's disease (also known as Cushing's syndrome) occurs when adrenal glands produce too much cortisol. Cortisol is sometimes called a “stress hormone” and has a critical role in the body – it helps dogs function in stressful situations. It does so by regulating several functions, such as blood sugar, metabolism, skin condition, and more.
Three causes of Cushing's syndrome in dogs
1. Pituitary gland tumor.
85% of canine Cushing's patients have a tumor on the pituitary gland. This tumor can be malignant or benign, but either way, the complicated position prevents the gland (located in the brain) from proper functioning. The tumor-affected pituitary gland begins to overproduce a hormone that alerts the adrenal glands to overproduce cortisol. If the tumor doesn't grow, the condition can be managed, and the dog's symptoms are only related to cortisol. But if the tumor does grow, it may start to impact other centers in the brain, leading to neurological symptoms too. This development of the disease makes its management very difficult.
2. Adrenal tumor.
15% of dogs with Cushing's have a tumor on one or both adrenal glands. Just like with the pituitary tumor, the mere presence of the tumor (whether or not it's malignant) is disruptive to the proper functioning of the adrenals and results in the overproduction of cortisol.
3. Long-term use of steroids.
This is a rare case, but it does happen. Some dogs can develop Cushing's disease as a result of being overmedicated with steroids. If caught early enough and taken off the steroids, the condition can be reversible.
Symptoms of Cushing's in Dogs
This disease has many symptoms that show up gradually and are not instantly noticeable. It takes time for the owners and vets to pick up on all of them and connect them together. Some symptoms might initially even get attributed to other conditions. Cushing's syndrome mainly affects middle-aged and elderly dogs, but that doesn't mean young dogs are immune to it. Here are the most common symptoms:
- Excessive drinking – the dog constantly appears thirsty and will drink large amounts of water at once.
- Excessive urination – the dog will need to pee very frequently, possibly even having accidents in the house. Urinary tract infections are common, too.
- Increased appetite – as cortisol stimulates the appetite, the dog will appear to be hungry all the time. They may attempt to steal human food (even if otherwise well behaved in the kitchen) or continually plead for more meals.
- Enlarged belly – the dog's abdomen will look swollen, much larger than it did before.
- Skin problems – sudden changes may appear on the dog's skin (dark spots, thin skin, dry patches, hair loss, recurring skin infections, etc.)
- Excessive panting
- Low activity and lethargy – the dog is not excited to go out, lacks energy, seems unmotivated and unfocused.
Since cortisol keeps the body in a stress response, pay attention to any other behaviors that are out of the ordinary and appear distressing, even if they're not listed above!
The Risks and Limitations of Traditional Treatment Options
When your dog receives Cushing's diagnosis, the first thing that is usually offered or recommended is the traditional treatment for the disease, primarily with medication. And yet, many dog owners are desperate for an alternative. Suppose you don't have personal experience with your dog having an adverse reaction to medication or not qualifying for medication, to begin with. In that case, the yearning for a safe alternative may be difficult to understand at first. Let's take a closer look at the traditional treatment options for Cushing's disease and the warnings they come with.
FDA Approved Medication
This is the only approved drug that treats Cushing's syndrome, whether the tumor is on the pituitary gland or the adrenal glands. The drug suppresses the overproduction of cortisol in the adrenals. According to the FDA, Vetoryl® should not be prescribed to dogs with kidney or liver disease, is not compatible with several heart disease medications, and cannot be prescribed to pregnant dogs. The most common side effects of the drug include vomiting, diarrhea, lack of energy, lack of appetite, fatigue. The most severe side effects reported were shaking, bloody diarrhea, liver and kidney complications, collapse, destruction of the adrenal gland, and death. This medication is not safe to be handled by people who are pregnant or trying to conceive!
This is the only other approved drug, but can only be prescribed for pituitary-related Cushing's syndrome. Anipryl® is not recommended for aggressive dogs, as it may trigger unwanted behaviors. There is no information on whether this drug is safe for breeding, pregnant, or lactating dogs. There are several possible side effects, many of them neurological, such as agitation, changes in behavior, disorientation, irritability, increased anxiety, restlessness. Other side effects include (but are not limited to) weakness, ataxia, severe weight loss (canine anorexia), incoordination, cardiovascular issues, and respiratory issues.
Prescribing a drug “off label” means that a veterinarian can prescribe a human drug that has not been tested or approved for being used on dogs. All experience with the drug is experimental and based on personal accounts. Lysodren® is a human chemotherapy drug often prescribed for the treatment of Cushing's disease in dogs. There is no way to know how a dog's immune system will respond to a human drug. Just like the approved medication, off-label drugs can have severe side effects and require very close monitoring. Pregnant women should never handle Lysodren®! All dog owners need to use gloves when administering the tablets and handling their dog's urine, feces, or vomit, as the drug can still be present in them. You should never touch your skin, eyes, or mouth when handling this drug.
All three of these medications require constant monitoring, as the dose is likely to change over time. A dose that is too high can do serious damage to the dog. Veterinarians determine the dosage through regular blood tests and observation. As with all medication, some dogs respond well to the treatment, others don't respond at all, and some dogs respond with adverse effects.
DISCLAIMER: The information listed above is shared for educational purposes only. Additional information can be found on the FDA's website and the official medication guides for Vetoryl® and Anipryl®. You can also read the medication guide for Lysodren®, but know that this is a guide for human use, as this drug is not approved for dogs. Please don't make any decisions about your dog's medication before consulting with your holistic veterinarian!!!
When a tumor on the adrenal glands causes Cushing's syndrome, surgery could be an option – provided the tumor is not malignant, not too big, and it hasn't spread. Aside from the surgery's cost, which might be inaccessible to many people, the procedure itself is considered very high-risk. The only way to operate this condition is to entirely remove the tumorous adrenal gland(s), which is difficult because they lie between three arteries (aorta, the renal artery, and phrenicoabdominal artery). Not every surgeon is qualified to perform this kind of surgery. One veterinary expert explained that “removal of an adrenal tumor is generally considered to be one of the most difficult surgeries in all of the veterinary practice.”
There are many risks associated with this surgery. A survey of 63 dogs going through it found that 18 of them died in the surgery or due to surgery-related complications. Additional 4 dogs were euthanized on the table because their tumors were found to be inoperable. If the dog does survive the operation, they are surely looking at a longer lifespan, so there is no denying that surgery can be a success for some. But a realistic picture and the difficult truth is that this type of surgery is not an option for the vast majority of dogs and their owners.
CBD Can Help Manage Symptoms of Canine Cushing's Disease – Here's How
It's obvious now why a safe alternative is so necessary. When traditional medicine comes to the end of the rope, holistic veterinary medicine steps in and provides new hope. CBD is an incredibly promising, natural, and holistic way of managing Cushing's syndrome in dogs. It does so through several channels of support.
Antitumor and Anticancer Effect of CBD
As mentioned, Cushing's disease is the consequence of a tumor on a pituitary gland or adrenal gland. Several research studies show CBD has an antitumor and anticancer effect. It has been proven to attack, shrink, and even kill cancerous cells specifically. This makes it a notable option for dogs with a malignant tumor that is inoperable. Even if the tumor is benign, research has proven that CBD prevents tumors from growing and spreading, which is an important factor in managing Cushing's in dogs. When the tumor becomes too big, the dog's life ends very quickly. This is where CBD has immense potential as a treatment option to prolong the dog's lifespan significantly.
CBD's Effect on the Pituitary Gland
Research shows that CBD can impact the functioning of the endocrine stress axis, also known as the hypothalamic-pituitary-adrenal (HPA) axis. In Cushing's syndrome, the tumor-affected pituitary gland overproduces a hormone that keeps alerting the adrenal glands to produce cortisol, which leads to a disbalance in the body. CBD's impact on the HPA axis can influence and regulate the pituitary gland's hormone production, working in favor of somewhat restoring hormonal balance in the dog's body. Because of the tumor, the disease is still considered terminal, but CBD's influence on the pituitary gland can slow down the process of hormonal imbalance in the endocrines. Remember, 85% of all dogs with Cushing's syndrome have a pituitary tumor that cannot be cured or removed! This makes CBD a highly relevant holistic treatment option.
CBD's Regulation of Cortisol
A tumor is the biggest issue in dogs with Cushing's, but cortisol is the second-in-command. The overproduction of this hormone is what causes almost all of the symptoms. The best way to manage Cushing's disease is to regulate the cortisol levels in the dog's body – thankfully, CBD has been studied in this area as well. A human study showed that CBD could decrease cortisol levels, meaning it might help alleviate several of the dog's symptoms directly related to cortisol excess. More studies on this are still needed, but the current information looks very promising.
The Safety of CBD
The reason why CBD is so favored in holistic veterinary medicine is that it doesn't have any adverse psychoactive effects (as opposed to THC). Dogs do not get “high” from taking CBD but still get all the benefits that cannabis-derived products are known for. CBD is not toxic to dogs or humans, it is very safe to use, and it almost doesn't have side effects (some dogs do experience temporary dryness of mouth, drowsiness, and diarrhea). The safety aspect makes it a worthy alternative for a dog whose immune system is already significantly weakened by the disease and aggressive treatments.
Receiving the news that our dog is terminally ill is one of the most difficult things to experience as a dog owner. It is very hard to accept that our dog's condition cannot be cured. Cushing's disease can be managed, though, and it's important to consider our dog's quality of life when choosing the treatment plan. The research surrounding CBD's impact on tumors, cortisol, and the pituitary gland makes it very relevant for dogs with Cushing's syndrome. It is a safer option for many dogs (and their people) who are not compatible with traditional medication. CBD has the potential to safely slow down the disease and give the owners of terminally ill dogs the one thing they wish for – time.
“Treating Cushing's Disease in Dogs.” FDA, 23/10/2015.
Weir, Malcolm. Ward, Ernest. “Cushing'sDisease in Dogs.” VCA Hospitals.
Massi, Paola. Solinas, Marta. Cinquina, Valentina. Parolaro, Daniela. “Cannabidiol as potential anticancer drug.” PMC, 17/04/2012.
Murphy, L. Laura. Muñoz, M. Raúl. Adrian, A. Brian. Villanúa, A. Marı́a. “Function of Cannabinoid Receptors in the Neuroendocrine Regulation of Hormone Secretion.” Science Direct, 12/1998.
Zuardi, A. W. Guimarães, F. S. Moreira, A. C. “Effect of cannabidiol on plasma prolactin, growth hormone and cortisol in human volunteers.” PubMed, 02/1993.
“Vetoryl® Capsules (trilostane).” Dechra.
“Anipryl®.” Zoetis, 07/2019.
Gollakner, Rania. “Mitotane.” VCA Hospitals.
Brooks, Wendy. “Adrenal Tumor Treatment in Cushing's Syndrome.” Veterinary Partner, 30/07/2020.
Luna’s passion for learning about canine psychology and behavior began when she adopted a severely reactive puppy from a local shelter. She is now a big advocate for positive reinforcement and compassionate training. As a writer, she strives to spotlight the topics that fly under the radar and be the voice for all who cannot speak for themselves.
6 thoughts on “Hope on the Horizon: CBD for Cushing’s Disease in Dogs”
One side effect of CBD oil that was not mentioned is the increase of liver enzymes. I have been reading all I can the past few days regarding CBD oil for dogs and quite a few articles have listed this side effect. I think this is important information that should be included in this article.
The question of CBD increasing liver enzymes is a result of an experimental study on six mice that first drew this connection – but only after giving the mice incredibly high doses of Cannabis extract, which is not identical to CBD oil. (Here is the full study: https://www.mdpi.com/1420-3049/24/9/1694/html).
It’s important to look at this issue from multiple perspectives and take other research into account as well. I am very fond of this particular article (https://journals.sagepub.com/doi/10.1177/2397847320922944) that combed through a lot of scientific papers, looked at human studies and animal studies, and came to this conclusion: “Based on the available data, it may be concluded that there is a low probability of serious hepatotoxicity at the high therapeutic doses that are used and a much lower risk of adverse hepatic effects and a potential for hepatoprotection effects at the lower doses commonly used in dietary supplements and food products. However, a detailed safety study in rats using highly purified CBD rather than enriched Cannabis extracts is needed, enabling the determination of hepatic as well as other tissue effects and potential margin of safety.”
I always try to find resources that take different factors into consideration and are able to critically examine individual research papers. I still stand by my statement that CBD oil is very safe, as this is continually supported by multiple studies. With that said, more studies are needed to determine the exact details of what a safe high dose is. For now, lower doses should not be causing issues.
I hope this clarification was able to help. Thank you for bringing up this topic and opening this important conversation! 🙂
Is it safe to give your dog CBD oil while also taking Anipryl? The anipryl is taken in the morning but she does not sleep at night she paces and walks in circles and I thought of giving her CBD in the evening so she could sleep is this safe
I’m so sorry for a belated response! CBD can definitely interact with certain medication (making them less effective or increasing the side effects), so you’ll need to get your vet’s approval before you try this out. Any time your dog is on medication your veterinarian needs to be consulted on the dietary supplements, to stay on the safe side of things.
If you don’t get a green light for CBD, ask the veterinarian for natural alternatives to help your dog calm down and sleep. My dogs respond very positively to having lavender essential oil diffused in the room. There is also dog massage, playing white noise, mental exercises before sleep time, melatonin … you definitely still have options! I hope your vet will point you into the right direction.
I’m wishing you the best of luck & sending much love to your dog!
How much CBD should a dog be given each day? My dog is 27 lbs.
Is there a specific form of cbd that works best. Full spectrum vs broad spectrum etc.