Important safety information
For cats: The most common adverse reaction recorded in clinical trials was vomiting. Other adverse reactions were: lethargy, decreased appetite, weight loss, and diarrhea. Use with caution with concomitant extra-label use of ivermectin.
The safe use of Comfortis in breeding, pregnant, or lactating cats has not been evaluated.
For dogs: The most common adverse reaction reported is vomiting. Other adverse reactions reported in decreasing order of frequency are: depression/lethargy, decreased appetite, incoordination, diarrhea, itching, trembling, excessive salivation and seizures.
Following concomitant extra-label use of ivermectin with Comfortis, some dogs have experienced the following clinical signs: trembling/twitching, salivation/ drooling, seizures, incoordination, excessive dilation of pupils, blindness and disorientation. Post-approval experience continues to support the safety of Comfortis when used concurrently with heartworm preventatives according to label directions.
Use with caution in breeding females and dogs with pre-existing epilepsy. The safe use of Comfortis in breeding males has not been evaluated.
View full product label for complete safety information.