Apoquel and Cytopoint, both manufactured by Zoetis, have been around for some time now – eight years and five years, respectively. They represent the newest and most effective drugs in the veterinary arsenal to stop itching in dogs with allergies – but their use is not without risk of side effects or contraindications. That said, these drugs have vastly improved the lives of many severely allergic dogs without any ill effects whatsoever.
Before I explain why these drugs are so ground-breaking, allow me to briefly explain why allergies are so hard to treat in some dogs, and how the veterinary medication predecessors to these drugs differ.
DOG ALLERGY TREATMENTS
The hallmark of allergies in dogs is normal, healthy-looking skin that seems to itch. The offending allergen is either inhaled (atopy) or ingested (food allergy). Inhaled allergens frequently cause seasonal itching (only in the spring or only in the fall). Food allergy typically causes itching year-round.
The goal of allergy therapy is to eliminate the itch. If you don’t stop the underlying itch, your dog will scratch, chew, bite, and rub his way to secondary skin infections, which add a second layer of itch and discomfort.
There is a complex, biochemical cascade, with lots of different mediators, that occurs between the allergen first being recognized by the body and the result, which is skin inflammation and itch. In broad terms, treatments for managing the allergic itch block or interrupt this cascade at various points. The more complete the block or interruption, the better the allergy itch control.
It would be ideal if it was possible to completely prevent the dog from coming into contact with any of the substances that he’s allergic to, but in the case of atopy, this is pretty much impossible. It is possible in the case of food allergies – if you can identify the food or foods that your dog is allergic to by undertaking a diet trial. To properly rule out food allergy, you must feed either an extremely limited-ingredient diet containing only ingredients that are novel for the dog (he’s never eaten them before) or a hydrolyzed protein diet and nothing else for eight to 12 weeks, and see if the itch subsides. (If it doesn’t, atopy, not food, is likely the issue.)
Most of the medications used to relieve allergy-caused itching don’t manage food allergy itch very well, so if you skip this step, you may end up disappointed and frustrated.
In lieu of complete protection from contact between the dog and the substances he’s allergic to, the gold standard for managing allergies is still allergy testing and immunotherapy (allergy shots), just like those that humans get.
The goal of this therapy is to stimulate the dog’s body to create antibodies against his allergens, thereby blocking the inflammatory cascade right at the starting gate. Unfortunately, this is not the most popular approach to allergy management for pet owners, as it is expensive, labor intensive, not without risk, and comes with no guarantee.
So we move on to medications. Antihistamines are inexpensive, available over the counter, and safe. The problem is, they don’t work very well in dogs. They definitely won’t help in the face of a full-blown allergy inflammatory breakout. Blocking histamine at that stage is just too late.
Probably the most useful place for antihistamines would be leading up to your dog’s allergy season. If you know he has trouble in the fall, starting an antihistamine ahead of time might help dampen his initial reaction to his allergens. Or, if a prescription medication is helping but not giving 100% relief, sometimes adding an antihistamine will help. Discuss this with your veterinarian.
Steroids work well to stop allergic itching and their effect is immediate, but they come with a plethora of negative effects on the body, including immune suppression. I’ll still prescribe them for severe, acute cases, but only in the beginning, to get the inflammation under control. After that, we look for a safer, long-term solution.
Atopica (cyclosporine) was approved by the Food & Drug Administration in 2003. It’s a reasonable alternative to steroids for longer-term allergy management. But like steroids, it can cause immune suppression. It also takes too long to kick in. It can be as long as four to eight weeks before you see maximal response – way too long for the allergic dog and his owner to wait.
NEWER ALLERGY MEDICINE FOR DOGS
The newest allergy treatment options are Apoquel and Cytopoint. These medications interrupt the inflammatory cascade at different points. They are both rapid-acting and have minimal side effects. There are pros and cons to each which we will discuss.
Apoquel (oclacitinib maleate) blocks the effects of cytokines, which are pro-inflammatory proteins heavily involved in the allergy cascade. It is an oral tablet administered twice daily for 14 days, then once daily. It takes effect quickly, within 24 hours, and works really well for many dogs. Side effects are not common, but vomiting, diarrhea, loss of appetite, and lethargy have been reported.
The results of safety testing done on Apoquel suggest the possibility of some immune suppression when using this drug. This is one of the potential downsides of Apoquel. Some dogs developed significant infections (pneumonia) and demodectic mange, which typically occurs in the face of immune suppression. This was especially true in puppies, which is why the drug is labeled for use only in dogs 12 months or older. It’s also not for use in breeding dogs or pregnant or nursing mothers.
Neither I nor my colleagues have had issues in our clinic with Apoquel causing immune suppression, and I do not hesitate to use it in appropriate patients. But the possibility makes careful monitoring of these patients prudent.
There is also a label warning – “Use with caution” – regarding the use of Apoquel in dogs with tumors. Cytopoint may be a better choice for these dogs, since it has no warnings or concerns regarding tumors.
Sometimes Apoquel works great when dosed twice a day, but not as well when the dose is reduced to the once-daily, long-term dose. I see this a lot in the clinic, and it’s so disappointing for the pet owner. A number of owners have asked me if they can just continue with twice-daily dosing. Unfortunately, long-term safety studies at this dose have not been done. Apoquel can be used this way off-label, but there is no way to know if it’s truly safe for your dog.
My preference for these dogs is to continue the Apoquel once a day (as labeled) and add Cytopoint. These two medications are perfectly safe to use together, and in my experience, this combination is often the magic bullet for those difficult-to-manage allergy dogs.
Cytopoint (lokivetmab) is a monoclonal antibody against the cytokine interleukin 31 (IL-31), a big player in the allergy inflammatory cascade. It is an injectable medication, administered under the skin. It takes effect quickly, relieving itch within 24 hours, and typically lasts anywhere from four to eight weeks.
Side effects are rare, but once again, vomiting, diarrhea, loss of appetite, and lethargy have been reported. Pain or discomfort at the injection site occasionally happens, but typically is mild and short-lived if it occurs. Cytopoint is not immune-suppressive, and there are no warnings or concerns about tumors.
However, the one potential downfall of Cytopoint is that the dog can form antibodies against it. If this happens, then the medication will lose its effectiveness – forever. I haven’t seen this yet, but if your dog is responding well to Cytopoint at first, and then less and less so, this is likely what’s happening. I hope I never see it.
As a practicing veterinarian, I really like Cytopoint. If I had an allergic dog, I would choose Cytopoint first.
If you have an allergic dog, hopefully this information helps you as you navigate your journey. As always, the best advice for you and your dog comes from your veterinarian.