It is a rare dog indeed that at some point in their life has not been prescribed prednisone for dogs.
In part this is because itchiness is extremely common, and prednisone is extremely good at stopping itches, but also because a dose of prednisone often produces an instant and discernible improvement.
Whilst this may make prednisone sound like a wonder drug, this is far from the truth because there are a wide number of side effects of prednisone for dogs, plus the drug can also mask developing disease with disastrous consequences.
1. What is Prednisone for Dogs?
Prednisone belongs to a class of drugs called corticosteroids, or is what ‘apple’ is to ‘fruit’.
When prednisone is given to dogs it is broken down to a more active molecule called prednisolone.
Thus some vets will prescribe the precursor drug, prednisone, whilst others opt to save the body a bit of work by using prednisolone.
The key to understanding why prednisone is so popular is to know more about corticosteroids and their actions.
Steroids are naturally occurring chemicals that are manufactured in the body in the adrenal cortex (this is a small gland that sits on top of the kidney, as a cherry on a cupcake).
The natural steroid helps the body cope with the ups and downs of everyday life.
Indeed a condition known as Addison’s disease occurs when the adrenal cortex is damaged and can’t produce steroids.
The result is a dog that can’t cope with stress and becomes extremely ill with muscular weakness, sickness, and diarrhea.
As for the role of prednisone in veterinary medicine, it has a number of properties which make it so popular, such as:
- It is a potent anti-inflammatory
- It has an immunosuppressive role
- It is anti-neoplastic (anti-cancer)
So what does this mean in practical terms and when might your dog be prescribed prednisone?
Anti-inflammatory means just that, it’s a useful way at reducing inflammation.
This makes prednisone for dogs itching a popular choice as it produces an almost instant relief from the misery of scratching, licking, and chewing.
With regards to suppressing the immune system, this can be incredibly important in conditions such as auto-immune conditions, where the body attacks its own tissues.
This can lead to serious complications such as profound anemia or serious skin conditions, but prednisone can ‘switch off’ that inappropriate reaction and allow the dog to recover.
Prednisone for dogs cancer is another important role.
This is because prednisone has a number of effects on cancer cells that play an important role as a chemotherapy drug.
This includes making the cancer cells less ‘sticky’ so they are less able to seed off and establish secondary tumors, and also shrinking down the size of some tumors.
2. Is Prednisone Safe for Dogs?
To be safe steroids need to be used responsibly and under veterinary supervision.
In all but the most straightforward cases, your vet will want to reach a diagnosis before starting treatment with steroids.
This is because:
- Steroid usage can interfere with reliable test results, throwing up false negatives and false positives, making a diagnosis post-treatment difficult or impossible.
- Steroids give a feeling of euphoria, so the patient can appear to get better when in reality they are deteriorating. This can mask warning signs leading to a potentially catastrophic worsening of the condition.
- Steroids have a wide range of undesirable interactions with other drugs, so their use needs careful consideration
- Steroids can worsen conditions such as diabetes or infections
- Steroids can cause illnesses such as Cushing’s disease when used in the wrong way
That said, once the vet has reached a diagnosis, steroids can be hugely beneficial and even life-saving in a range of conditions.
Those where prednisone is most commonly called into action include:
- Skin allergies
- Autoimmune conditions where the body attacks its own cells. This includes serious conditions such as autoimmune hemolytic anemia (red blood cell destruction), autoimmune thrombocytopenia (clotting platelets are destroyed), and pemphigus.
- Inflammatory conditions such as IBD (Inflammatory bowel disease) or sterile meningitis.
- Cancers, especially conditions such as lymphoma or mast cell tumors.
3. Prednisone Side Effects for Dogs
When used in the wrong way, steroids can either cause side effects in the short term (such as vomiting) or in the long term (such as dependency and Cushing’s disease).
A. Short Term Side Effects
As a pet parent, if your dog is prescribed prednisone the most immediate problem you’ll notice is the dog eats and drinks more.
Excessive drinking can lead to accidents in the house, even for dogs that are properly potty trained.
Likewise, the ravenous appetite can cause some dogs to steal food and is a common cause of weight gain.
Unfortunately, these side effects are to be expected, so don’t be alarmed if your dog becomes food and water-obsessed.
Whilst inconvenient and undesirable, hunger and thirst aren’t generally harmful to the dog, however, some of the other short term side effects are.
The most serious include gastric ulceration.
This is most likely to occur when the steroid is given on an empty stomach.
This can lead to damage to the stomach lining and ulcer formation.
The signs of gastric ulcers include poor appetite and vomiting, of which vomiting blood is a worrying sign.
With this in mind if your dog does not eat but is on steroids, phone your vet to take their advice about whether to give the medication or not.
Also in the short term, giving steroids can cause serious side effects if the dog is taking other drugs, such as painkillers from the non-steroidal family.
These two different families of drugs both have gastric ulceration as a recognized side effect, so the chances of a serious problem are greatly magnified.
B. Long Term Side Effects
Long term side effects do depend on the dose.
For example, a dog on long term high doses of steroid for itchy skin may find himself putting on weight at an alarming rate.
Also in the long term steroids have a variety of unwanted effects such as thin skin, muscle weakness, and a potbelly.
You and your vet need to have a discussion about how essential it is the dog takes prednisone and if there are any alternatives.
For example, a dog with itchy skin may be able to take an alternative drug.
Whilst for a dog with cancer the alternative to not taking steroids could be death, so putting up with the side effects is a price worth paying.
The bad news is that the long a dog takes steroids, the longer it takes for him to come off them.
Suddenly stopping the steroids can cause catastrophic problems such as an Addisonian crisis where the dog collapses, and in extreme cases could die.
To avoid the long term consequences most vets take two precautions. These are:
- To wean the dog down to the lowest effective dose
- To put the dog on alternate day therapy
Alternate day therapy is essential for dogs on long term treatment, as it gives the body a chance to be less dependent on steroids.
The idea is to give a double dose but every-other-day, giving the dog a steroid-free day in between.
This allows the dog to derive the beneficial effects of the prednisone but allows the body to make its own steroid (and reduce its dependency on tablets) of the ‘off’ day.
4. How Long Can a Dog Stay on Prednisone?
Generally, the aim is for the dog to take steroids for the shortest time possible.
However, a dog with a long term illness such as IBD or an autoimmune disease may need to stay on steroids for life.
This can be safely achieved by the use of alternate-day dosing (as described above).
5. Prednisone Dosage for Dogs
The dosage of prednisone varies widely.
The dose to reduce inflammation is generally around 1 – 2 mg/kg body weight, whilst anti-cancer or immunosuppressive doses are higher at 2 – 4 mg/kg body weight.
That said, ultra-low doses such as ¼ mg/kg are often all that is needed for mild inflammation.
A large dog such as a mastiff on treatment for lymphoma can easily need to take around 140mg of steroid a day, making prednisone 20mg for dogs the easiest way to get the tablets in.
For smaller dogs or smaller doses, prednisone 5mg for dogs provides more flexible dosing.
Again, the general rules are that the tablets should be given with or after food, and if your dog is unwell or vomits then contact your vet for advice about whether to give the next dose. For all other dog-medication please refer to our index page here.