Soothing Your Pooch’s Itch with Apoquel – All the Facts About Pruritus, Allergies, and Apoquel for Dogs

Is your dog suffering from itchiness caused by dermatitis or allergies? If yes, then your veterinarian may have prescribed topical glucocorticoid medications or oral cyclosporine to treat your dog’s condition. But there’s a recently-developed drug that’s starting to gain traction in veterinary medicine as an alternative to steroids and cyclosporine – and that’s Apoquel.

What is Apoquel and how does it treat allergies and itch in your dog? This article will shed some light on how Apoquel works, what dosage is effective, and other pertinent information about this relatively new medication. We’ll also feature some tips on how to give Apoquel to your dog safely and successfully.

• • • • • • • • • What is Apoquel?
                • What Does Apoquel for Dogs Treat?
                  • Canine Atopic Dermatitis
                • What Are Dogs Allergic To?
                • Dogs Predisposed to Atopic Dermatitis
                • Symptoms of Canine Atopic Dermatitis
                • How Does Apoquel Work?
                • Recommended Dosage and Duration of Apoquel Therapy for Dogs
                • Apoquel Side Effects in Dogs
                • When Should Apoquel Use Be Avoided?
                • Drug Interactions with Apoquel
                • Is Apoquel a Hazardous Drug for Humans?
                • Caring for Your Dog on Apoquel Therapy

What is Apoquel?

Apoquel is the brand name for oclacitinib, a new medication in veterinary dermatology. It is used to control itchiness and other symptoms of atopic/allergic dermatitis in dogs. Apoquel was developed as a new alternative to the typical steroid or cyclosporine medications conventionally given to treat itchiness in dogs.

Apoquel is classified as a Janus Kinase (JAK) inhibitor. It works on the dog’s immune system to help stop itchiness rapidly. The medication is taken orally and is only available per veterinarian’s prescription. It comes in tablets that need to be taken once or twice a day, depending on the dog’s body weight and intensity of the allergic condition.

Zoetis is the company behind the discovery and development of Apoquel. It was formerly the animal health branch of giant pharmaceutical company Pfizer. Apoquel has been FDA-approved solely for dogs’ use and became available in 2013.

What Does Apoquel for Dogs Treat?

Itchiness or pruritus is the main target of Apoquel. Most often, this bothersome symptom comes from atopic dermatitis, otherwise known as allergic dermatitis. Let’s have a quick overview of this skin condition in this section.

Canine Atopic Dermatitis

Canine atopic dermatitis is the most common skin condition seen in dogs. It is also called canine atopy and allergic dermatitis. This skin problem refers to an overreaction of the dog’s body to certain environmental substances. When the dog comes into contact with an allergy-inducing substance, his skin flares up with redness and itch. Some gastrointestinal symptoms may also show up.

The condition often starts early on during a dog’s life. Symptoms may begin to manifest as early as 6 months of age. It then comes and goes until the dog is around 3 years old. Some cases persist for longer years.

What Are Dogs Allergic To?

Common substances, even those that aren’t inherently harmful, may cause atopic dermatitis in dogs. Examples of these substances include:

• Dust mites
• Pollens from weeds, trees, flowers, and grasses
• Mold spores
• Certain food items (highly individualized and depending on the dog)
• Fleas, particularly to the proteins found in their saliva

Now, atopic dermatitis may lead to secondary skin infections when not given prompt attention and treatment. Bacteria (staphylococcus) and yeast (Malassezia) may overgrow and create hypersensitivity in the dog, creating more inflammation and other problems in his skin.

Dogs Predisposed to Atopic Dermatitis

Atopic dermatitis is hereditary by nature. That means the allergies to specific substances are passed down from the sire and dam to the puppies. Several breeds appear more predisposed to atopic dermatitis and allergies, including the following:

• Terriers (especially West Highland White Terriers)
• Bulldogs
• Labrador Retrievers
• Golden Retrievers
• Old English Sheepdogs
• Lhasa Apsos
• Dalmatians
• Irish Setters

However, any breed of dog can get atopic dermatitis, including mixed-breed dogs.

Symptoms of Canine Atopic Dermatitis

You’ll see these symptoms in a dog with allergic dermatitis:

• Pruritus or itching on different parts of the body
• Dry, crusty, or oily skin
• Patchy or inconsistent hair loss
• Thickened skin
• Reddened and inflamed ear flaps

How Does Apoquel Work?

Now that you have a background of canine atopic dermatitis, it’s time to see how Apoquel works in dogs. We’ll start by explaining what happens to the dog’s immune processes during a bout of allergic dermatitis. 

Canine atopic dermatitis actually has unclear pathogenesis. However, when a dog is exposed to an allergen, certain chemicals involved in the immune function react to proteins from the allergens. Particularly, small inflammatory signal proteins called cytokines are activated and released.

As cytokines are released inside the dog’s body, they bind to and activate type I and II cytokine receptors. These receptors transmit signals between cells through an enzyme family called Janus kinase (JAK). 

Now, activation of JAK1 and JAK3 pathways allows the cytokines to activate, thereby creating skin redness and pruritus (itch). Specifically, proteins mediated by the JAK1 and JAK3 pathways include IL-2, IL-4, IL-6, IL-13, IL-31, and thymic stromal lymphopoietin. All these interleukins and proteins help trigger an inflammatory reaction against foreign body invaders such as allergens.

Apoquel, or oclacitinib, is a Janus kinase inhibitor. This medication hinders the production of cytokines by inhibiting JAK enzymes. The medication appears to strongly inhibit JAK1 and JAK3 production. Since oclacitinib inhibits JAK1, it also stops the creation of a specific interleukin related to itchiness in canine atopic dermatitis, IL-31. As a result, the immune system response is modulated, thereby reducing inflammation and itchiness in dogs exposed to allergens.

Oclacitinib has a rapid onset of effect because it is quickly absorbed by the dog’s body after oral administration. It reaches a peak concentration in the blood plasma one hour after ingestion, making it control pruritus right away. The drug appears to have a slower onset of action for inflammation.

Oclacitinib’s bioavailability is at 89%. The drug is cleared from the dog’s body mainly via kidneys and biliary elimination. 

Recommended Dosage and Duration of Apoquel Therapy for Dogs

The recommended dosage of Apoquel in dogs is 0.4 to 0.6 mg per kg of body weight. The dose is given twice a day, every 12 hours, for the first two weeks (14 days) of therapy. After that, the medication is given every 24 hours as needed to relieve itch.

Most veterinarians recommend that Apoquel be used for dogs with seasonal environmental allergies. The medication will be given twice a day for 2 weeks, then once a day for the remainder of the season. As such, the dog will get treated only until the itch and inflammatory symptoms are controlled within the allergy season, so the therapy doesn’t have to be long-term.

Some veterinarians prefer to give the initial Apoquel dose twice a day for one week and see if the dog

has significant improvement in his symptoms before proceeding further. Other vets may prescribe a lower dose to check if the pet tolerates it while getting the desired effect. The bottom line is that Apoquel dosing is still largely individualized depending on a dog’s particular medical history. Veterinarians follow the strict dosing schedule and even go below it, but never prescribe doses higher than the general recommendation.

The tablets are supplied in 3.6 mg, 5.4 mg, and 16 mg strengths. Your veterinarian will assist you in determining how many tablets (or half-tablets, as necessary) you should give to your dog.

Apoquel is most suitable for controlling acute flares of itch from canine atopic dermatitis. It should be given while actively preventing the entrance of known allergens and irritants to your dog’s skin and body.

Never administer Apoquel without your veterinarian’s approval. Only give your dog the prescribed dosage as well. Apoquel has potentially serious side effects, so giving higher doses without prior knowledge or approval from your veterinarian may result in complications in your dog’s immune system.

Apoquel Side Effects in Dogs

Apoquel is relatively safe to use for most dogs. But there are certain side effects that you should watch out for. The typical side effects your dog may exhibit under Apoquel therapy include:

• Diarrhea
• Vomiting
• Decreased appetite
• Lethargy

However, be alert for more serious side effects such as:

• Extreme thirst (polydipsia)
• Fatigue
• Lumps or growths underneath the tissues (neoplasia), especially near the throat and abdomen
• Increased susceptibility to infection
• Pneumonia
• Lymphoma
• Increased aggression

Anecdotal reports from some pet owners reveal that their dogs developed yeast overgrowth, skin infections, runny nose, and other symptoms as a result of immunosuppression. These symptoms appeared after a few weeks of taking Apoquel. Indeed, there is a possibility that your dog’s immune system becomes weakened because the drug itself works that way. Apoquel inhibits modulator cells to stop itch and inflammation, but it also slows down your dog’s immune system, leaving them susceptible to different illnesses and growths.

When Should Apoquel Use Be Avoided?

Dogs in certain circumstances are not allowed to use this medication for controlling their pruritic skin conditions. Given the potentially serious side effects of Apoquel, its use should be avoided in:

• Dogs that are less than 12 months old
• Dogs with less than 3 kg of body weight
• Breeding dogs
• Pregnant and lactating dogs
• Dogs with known allergic reaction or hypersensitivity to oclacitinib
• Dogs with heart, liver, and kidney disease
• Dogs suffering from chronic inflammatory conditions such as inflammatory bowel disease or immune-mediated polyarthritis
• Dogs with serious illnesses such as cancer, hyperadrenocorticism, progressive malignant neoplasia, and heartworm
• Dogs taking immunosuppressive chemotherapy such as azathioprine, methotrexate, mycophenolate, and similar drugs
• Dogs with current or recent demodectic mange, as Apoquel may exacerbate or cause a recurrence of the condition

Note that because of Apoquel’s possibly serious side effects, many dog owners and veterinarians choose to use the drug on a short-term basis only.

Drug Interactions with Apoquel

Currently, Apoquel has no known drug interactions. It can be safely used in dogs receiving vaccines, allergy immunotherapy, antihistamines, cyclosporine, anti-seizure medications, and non-steroidal anti-inflammatory medications (NSAIDs).

The short-term use of Apoquel has proven to be safe. However, the use of Apoquel with long-term corticosteroid therapy hasn’t been evaluated yet. Veterinarians advise against using the drug while on continuous steroid therapy to be on the safer side.

Still, inform your veterinarian about all medications your dog is taking, including herbals, supplements, prescription, and over-the-counter medications. Keep in mind that Apoquel is a relatively new entrant to veterinary pharmacology and will definitely be subjected to more research about potential drug interactions.

Is Apoquel a Hazardous Drug for Humans?

Hazardous Drug classification means that a certain medication poses a risk to health by merely handling it. Drugs included in this category typically include potent medications that can cause cancer or otherwise be harmful to human fetuses and vital organs. Cyclosporine, paroxetine, and strong chemotherapeutics are included in NIOSH’s Hazardous Drug List.

Now, Apoquel (oclacitinib) also poses a risk to become hazardous to humans. After all, medications under the JAK inhibitor family such as tofacitinib (used in humans for rheumatic arthritis and autoimmune diseases) can be found on the Hazardous Drug List. Tofacitinib, like Apoquel, may cause a marked suppression of immune function in humans and predispose users to lymphomas and mast cell tumors. 

Since Apoquel is a medication for dogs, it isn’t formally classified as a hazardous drug. But it is worth noting that while it is effective for quelling itch in dogs, its risks should be taken seriously both for dogs and humans. No, you certainly can’t take Apoquel, but you must wash your hands thoroughly after handling and giving the medication to your dogs to be on the safe side.

Caring for Your Dog on Apoquel Therapy

Here are some tips to help you manage your dog taking Apoquel:

• Complete the treatment duration as prescribed. Do not abruptly stop the medication even if your pet appears to be feeling better. Doing so will help prevent relapse and keep your dog more comfortable for longer. Only stop the medication immediately and inform the vet when your dog exhibits symptoms indicative of a side effect. Do note that tapering the dose is not necessary when stopping Apoquel, but some vets do this to prevent a sudden onset of the itchiness once the dog is off the medication.
• Blood works and monitoring may be required if your vet deems it necessary for your dog to take Apoquel for longer periods. This is done to ensure that your dog’s immune system remains intact and strong enough to protect him from illnesses while on Apoquel. Leukocytes, platelets, lipase, and cholesterol levels will likely be monitored by your vet from time to time.
• Report to your veterinarian if you haven’t seen improvement in the dog’s itchiness after the twice-a-day schedule of giving Apoquel. The medication likely won’t work, so your dog may be given other alternatives instead of Apoquel.
• Help your dog cope with stress as he undergoes Apoquel therapy. Extreme itch can be a huge source of stress in your dog and can take its toll on your dog’s body and health. [1] Keep him comfortable as you treat his itchiness with Apoquel to reduce his stress levels. You can also monitor his activity levels, tail-wagging [2], and general behavior to see if your dog’s stress is waning.
• You may safely give Apoquel with or without food. Most pet owners find it easier to give the medication with food, though.
• Always wash your hands after handling Apoquel. The drug may be quite harmful if fragments remain on your hands.

Wrapping It Up

Apoquel is a relatively new medication to treat itchiness caused by seasonal environmental allergies and canine atopic dermatitis. It works by mildly suppressing the immune system to stop the substances that cause itch and inflammation. It is generally safe to use, but the medication may produce serious side effects to watch out for. You must work with your veterinarian to ensure your dog stays safe while getting effective itch control on the medication.

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