The treatment of allergic skin disease in dogs has undergone a seismic shift over the past ten years. The use and abuse of harmful steroids such as prednisolone has given way to newer, safer and more effective alternatives.
Now more than ever, dogs that suffer from repeated ear infections, chronic foot licking, itchy skin and yeast infections have the chance to live normal lives. Nowhere is this more relevant than in our temperate Adelaide climate.
What Are The New Dog Allergy Drugs?
There are now four modern remedies that target the production of inflammatory cytokines in the allergic dog. In order of their release in Australia, they are:
- Apoquel
- Cytopoint
- Zenrelia
- Numelvi
Apoquel, Zenrelia and Numelvi are all janus kinase, or JAK inhibitors and come as daily tablets. They differ in their varying selectivity towards the three JAK enzymes and tyrosine kinase. These are the enzymes responsible for, among other things, the inflammatory response.
Cytopoint is the odd one out. It is a monoclonal antibody directed against the cytokine interleukin-31, and comes as a monthly injection given at your vet. This article won’t discuss it further but you can read all about it here.
For completeness, Atopica should also be mentioned. It was the first non-steroidal dog allergy treatment. It is now only used in special cases due to its lower efficacy, more obvious side effects and higher costs. These are the parameters against which all pharmaceuticals should be measured.
So let’s do it for the remaining three.
Efficacy of Apoquel, Numelvi & Zenrelia
Response rates of dogs with allergic skin signs are high to all three drugs. Apoquel, being the first, seemed like a wonder drug when it was released. It still works well, but in our experience the newer drugs tend to work better. There are still dogs, however for which Apoquel is the best option.
If one doesn’t work, it’s a very good idea to try another one. And of course, reevaluate the diagnosis. You can read more about the management of itchy dogs here.
Apoquel, Numelvi & Zenrelia Side Effects
All three drugs are extremely well tolerated, and it is rare that any of them will cause problems. They are a quantum leap from the old days of steroids.
The most common side-effects for all three drugs are gastrointestinal, such as vomiting, diarrhoea or not eating. We can also see lethargy in these dogs.
There’s a lot of talk about the different selectivity of the three drugs towards their target enzymes making a difference to their side effects, but this is more theoretical than practical. At regular doses, there doesn’t seem to be an obvious difference. One exception may be in response to vaccination.
It is possible that Zenrelia may blunt the immune response, although this has not been proven at normal doses. Nonetheless, it is generally advised to discontinue it around the time of vaccination.
More generally, we should always be alert to unexpected side-effects whenever we tinker with the immune system. For example, there has been suspicion that these drugs would increase the rate of some skin tumours, but this has not been observed in practice.
Cost of Apoquel, Numelvi & Zenrelia
If you have been recommended to try a JAK inhibitor for your allergic dog, it would be reasonable to look at the cost difference between the three drugs. They are priced similarly, but by looking through the different weight ranges you can see that sometimes one will be a lot cheaper than the others.
The following table provides a cost comparison between Apoquel, Numelvi and Zenrelia using current Australian prices. You can see that the cost changes dramatically in an unpredictable way based on the weight of the dog. This is due to the drugs existing in fixed tablet sizes, so generally the lowest prices will be where the tablet can be halved.
Look at a dog between 4.4 and 5.9kg for example. The cheapest option is Zenrelia, with Apoquel being only slightly more expensive. Numelvi for this dog will cost around twice as much. Then look between 9.1 and 13.4kg. Here Zenrelia and Apoquel end up being the ones costing almost twice as much as Numelvi.
Prices are listed as a percent value rather than a dollar amount as actual prices will vary. For a rough guide, at current prices ‘100%’ is equivalent to around three dollars.
| Dog weight (kg) | Apoquel cost | Numelvi cost | Zenrelia cost |
|---|---|---|---|
| 2.0 – 2.9 | – | 56% | – |
| 3.0 – 3.9 | 57% | 59% | 51% |
| 4.0 | 57% | 59% | 51% |
| 4.1 | 57% | 59% | 53% |
| 4.2 – 4.3 | 57% | 59% | 53% |
| 3.0 – 4.3 | 57% | 59% | 53% |
| 4.4 | 57% | 112% | 53% |
| 4.5 – 5.3 | 59% | 112% | 53% |
| 5.4 – 5.9 | 59% | 112% | 54% |
| 6.0 | 114% | 112% | 54% |
| 6.1 – 6.5 | 114% | 118% | 54% |
| 6.6 – 8.0 | 114% | 118% | 102% |
| 8.1 – 8.9 | 114% | 118% | 105% |
| 9.0 | 118% | 118% | 105% |
| 9.1 – 10.6 | 118% | 61% | 105% |
| 10.7 | 118% | 61% | 109% |
| 10.8 – 13.4 | 118% | 61% | 109% |
| 13.5 | 64% | 61% | 109% |
| 13.6 – 14.1 | 64% | 67% | 109% |
| 14.2 – 16 | 64% | 67% | 158% |
| 16.1 – 19.3 | 64% | 67% | 163% |
| 19.4 – 19.5 | 64% | 123% | 163% |
| 19.6 – 19.9 | 64% | 123% | 112% |
| 20.0 – 24.9 | 236% | 123% | 112% |
| 25.0 – 26.5 | 236% | 123% | 218% |
| 26.6 – 26.9 | 236% | 134% | 218% |
| 27.0 – 28.3 | 129% | 134% | 218% |
| 28.4 – 37.4 | 129% | 134% | 168% |
| 37.5 – 39.5 | 129% | 134% | 225% |
| 39.6 – 39.9 | 129% | 200% | 225% |
| 40.0 – 49.9 | 193% | 200% | 225% |
| 50.0 – 54.0 | 193% | 200% | 281% |
| 54.1 – 54.9 | 193% | 267% | 281% |
| 55.0 – 62.4 | 258% | 267% | 281% |
| 62.5 – 74.9 | 258% | 267% | 337% |
| 75.0 – 79.0 | 258% | 267% | |
| 79.1 – 80.0 | 258% |
Should My Dog Start a JAK Inhibitor?
Apoquel, Numelvi and Zenrelia are all prescription medicines, so they can only be started by a veterinarian. Therefore, the first thing to do is make an appointment.
Your vet will want to assess both your dog’s health history and their current problems. Next, they will probably test for and rule out the easier things, or suggest simple strategies that may help. The reason for this is that once you start a JAK inhibitor, it’s likely that you will continue it for life. You want to make sure that you’ve tried everything simpler first.
Your vet may even be the one to suggest these drugs. For the right dog at the right time they can give a wonderful boost to a dog’s quality of life. We all enjoy seeing that happen.
Once you start, you’re not locked into anything. You can stop them if they aren’t helping or there are unpleasant side effects. You can ask about trying another drug in the class, or only using them seasonally. And one thing is for certain: more options will become available in the future. It’s a great time to be a dog.