How to Care for a Dog Vomiting After a Cytopoint Injection
How long do Cytopoint side effects last in dogs?
Photo by Owner
"I have a question about Cytopoint side effects. My dog received it 4 days ago and shortly after passed out (sleep). Since then, she's been showing all the side effects described on the website: loss of appetite, lethargy, and vomiting (once a day).
She's drinking water and eating little bites here and there. My vet said they've never seen a reaction to the shot, and they don't think this is what caused the reaction, while I'm sure it is. It happened 20 minutes after she received the shot.
My question is: Have you seen this happen before, and what can I do to make her feel better? How many days does it usually last?"—Bori
Was Cytopoint the Reason for Your Dog's Reaction?
Allergic reactions are rare with Cytopoint, but some side effects do happen. When the medication was first approved, the researchers found no immediate hypersensitivity reactions (like wheals and vomiting), and only about 5% of the dogs felt pain at the injection site, similar to a placebo injection. (1) Like so many new drugs being approved, only 245 animals were included in the study, but the U.S. agency found that normal and proved that it was safe for all dogs.
The European Medicines Agency decided that Cytopoint's benefits are greater than its risks and approved this drug for sale in that continent even though they determined that side effects may occur in about 1 in 1000 dogs.
Most reactions to this drug are only pain at the injection site or allergic reactions with facial swelling and a rash. More severe reactions have been reported anecdotally, similar to what you describe, so Cytopoint may be causing your dog's illness.
How Long Will Cytopoint Last Inside Your Dog’s Body?
As far as how long it is going to be in your dog's body, the short answer is that we do not know. The half-life of the antibody in the injection has been reported to be about 16 days, (2) so every day, the amount in the body goes down a little. It stops working in most dogs in about 4 to 8 weeks, but just because it does not work anymore does not mean it is not present. After about 3 months, your dog will still have at least 1.5% of the drug in her body.
Whether it is a government-mandated vaccine or an injection that is supposed to help with an illness or chronic condition, any drug has multiple effects within the body—many of which we will only know with time, if we ever fully understand them at all.
If a vaccination or medication has been used for many years, there will be a lot of data on it. Cytopoint has not even been available for 10 years but was approved after showing no harm in the tested dogs. As mentioned above, only 245 dogs were needed to show this was safe.
There are now some anecdotal reports of Cytopoint causing autoimmune diseases like pemphigus and lupus, but no reports have been published. The number of adverse reactions reported to drug companies is very low, maybe only 10% of the true number in humans (3)and less in dogs, and the manufacturers can often claim that it was a pre-existing condition. (The "your dog was already sick" argument.)
What Can You Do if Your Dog Has a Severe Reaction to Cytopoint?
Whether you can do something for your dog now depends on where you are. If you have an emergency vet, I would recommend taking the dog there and telling them you suspect an adverse drug reaction.
The emergency veterinarian can perform a physical exam and do blood work. If they can find a problem, they may be able to help your dog, but if not, they can provide her with supportive care for at least a few days.
They can also report this as a suspected adverse drug reaction to the manufacturer of Cytopoint.
If you cannot take her to another vet, you can treat her for vomiting at home and call the Pet Poison Helpline at (855) 764-7661 or Animal Poison Control at (888) 426-4435. They may be able to give you suggestions to help her based on her signs.
Frequently Asked Questions
What Does Cytopoint Do to Dogs?
Cytopoint is a synthetic antibody that affects part of your dog's immune system so that it is not able to react to allergens. It targets a cytokine called Interleukin 31 (IL31), which is also important in the formation of red blood cells and protection against infectious diseases. Dogs with allergies produce too much IL31, so Cytopoint was developed to inactivate that immune pathway.
Is Cytopoint a Steroid?
Cytopoint is not a corticosteroid or an antihistamine but rather an alternative method developed to treat dogs with allergies. In the several years it has been available, the number of adverse reactions has been much more uncommon than with steroids like prednisone, and it works more effectively than antihistamines.
Are There Downsides to Cytopoint?
Cytopoint was approved for the treatment of dogs with allergies because the side effects are relatively rare. The downside is that about one in every thousand dogs that get one of these injections will have a reaction, and although it is usually mild (like pain at the injection site or a mild allergic reaction), the reaction may be severe (vomiting and lethargy) and may lead to an autoimmune disease like lupus.
Is Cytopoint Better Than Apoquel?
Apoquel is an immune suppressant that was approved after testing it on only 179 dogs for 28 days. Many drugs will not show side effects until later on, and in some cases, Apoquel can cause problems. But is Cytopoint a better option? Cytopoint is a synthetic monoclonal antibody that blocks part of the immune system, unlike a traditional immune suppressant that blocks all immune system reactions. The manufacturers consider it more specific, but it does have side effects for some dogs.
References
(1) Michels GM, Walsh KF, Kryda KA, Mahabir SP, Walters RR, Hoevers JD, Martinon OM. A blinded, randomized, placebo-controlled trial of the safety of lokivetmab (ZTS-00103289), a caninized anti-canine IL-31 monoclonal antibody in client-owned dogs with atopic dermatitis. Vet Dermatol. 2016 Dec;27(6):505-e136. doi: 10.1111/vde.12364. Epub 2016 Sep 19. PMID: 27647513. https://pubmed.ncbi.nlm.nih.gov/27647513/
(2) Outerbridge CA, Jordan TJM. Current Knowledge on Canine Atopic Dermatitis: Pathogenesis and Treatment. Adv Small Anim Care. 2021 Nov;2:101-115. doi: 10.1016/j.yasa.2021.07.004. Epub 2021 Sep 29. PMID: 35721364; PMCID: PMC9204668. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9204668/
(3) Srisuriyachanchai W, Cox AR, Kampichit S, Jarernsiripornkul N. Severity and Management of Adverse Drug Reactions Reported by Patients and Healthcare Professionals: A Cross-Sectional Survey. Int J Environ Res Public Health. 2023 Feb 20;20(4):3725. doi: 10.3390/ijerph20043725. PMID: 36834422; PMCID: PMC9959449. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9959449/
This article is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from your veterinarian. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
© 2023 Mark dos Anjos, DVM
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