Cytopoint is generally considered to be safe and well-tolerated in most dogs, but like any medication, it can cause side effects in some cases[2][3][5]. The most commonly reported side effects include:
- Lethargy, especially within 24-48 hours after injection[5]
- Gastrointestinal issues such as vomiting, diarrhea, and loss of appetite[2][3][7]
- Tenderness or pain at the injection site[2][7]
- Limping on the leg where the injection was given[2]
These side effects are usually mild and tend to resolve on their own within a few days[3]. Most dogs do not require additional treatment for these symptoms.
In rare cases, more serious reactions have been reported, such as:
- Allergic reactions (anaphylaxis) presenting as trouble breathing, severe grogginess, weakness, or collapse[2][3]
- Hypersensitivity or immune-mediated conditions, including autoimmune disorders like immune-mediated hemolytic anemia (IMHA)[1]
- Neurological symptoms such as seizures or increased pain in some dogs[1]
Reports from pet owners and some veterinarians have described serious adverse events, including gastrointestinal side effects, neurological issues, and, in rare and severe cases, death following Cytopoint administration[1]. However, these instances appear to be infrequent based on clinical studies and broader usage data[2][3][6].
It is recommended to monitor your pet closely after a Cytopoint injection, especially in the first 72 hours, and to contact your veterinarian if you notice any severe side effects or if your dog’s condition worsens[2].