Have a headache? Reach for the Advil! Just be sure that your cat and dog are not around. This common household medication falls within the class of nonsteroidal anti-inflammatory medications (NSAIDs), which includes aspirin, ibuprofen, naproxen and acetaminophen, and can have fatal results if swallowed by your furry friend. Ibuprofen should never be given to a pet for perceived pain or fever. Cats are especially susceptible to poisoning from this medication and just one 200 mg tablet can lethal. Dogs and cats alike, though, are at risk for poisoning at even small doses.