Common medicines to protect dogs and cats against fleas and ticks are causing them to develop tremors, seizures, or lose control of their movements, the Food and Drug Administration has warned.
FDA officials are alerting pet owners and veterinarians to be on the lookout for these potential side effects in the drugs, which pets take about once a month. The side effects have been observed in the medicines Bravecto, Nexgard, and Simparica.
Credelio, a similar medicine that was approved in January, is in the same category as the other drugs, but hasn’t been on the market long enough to observe the same side effects.
Agency officials encouraged veterinarians to work with pet owners to see whether their animals had a medical history that should be considered when deciding whether to prescribe the drug. They also asked both vets and doctors to contact the FDA if they notice the side effects in their pets.
“These products continue to be safe and effective for the majority of animals,” the FDA said in a statement.
The FDA is working with drugmakers to have them include the latest side effects on their packaging.
The most recent reactions in cats and dogs were discovered as FDA continued to monitor the drugs in the general pet population, something it does for all drugs it approves.
Drugs hit the market after government regulators have reviewed their testing information to see whether they are safe and effective. When medicines are used in the general population, however, other side effects or safety issues may come up because drugmakers do not test for every type of situation, such as if an animal has another illness or takes a different medicine that could trigger a medical issue. Sometimes after drugs are released they end up needing to add new warning labels, or to be pulled off the market, in extreme cases.
