Q: I have a 9 pound cat named Beauty and a 5 pound Chihuahua named Beast. Can I put half of Beast’s Monthly Flea & Tick Repellent on his skin and half on Beauty’s skin? This has enabled me to cut my monthly flea/tick prevention costs in half.
A It’s much safer to treat beauty with a product labeled for cats, since most topical dog flea and tick products contain substances toxic to cats.
The most common are pyrethroids, neurotoxins that paralyze and kill fleas, ticks, mites, and lice. Pyrethroids are synthetic versions of pyrethrins, natural insecticides derived from chrysanthemums. Compared to pyrethrins, pyrethroids are more toxic, have a longer duration of action, and are more stable in the environment.
One of the most popular pyrethroids is permethrin. Many other pyrethroid names end in “-thrin”.
Liver metabolism in cats and dogs is very different. Cats are extraordinarily sensitive to permethrin and other pyrethroids that are not harmful to dogs. Therefore, dog flea and tick repellents containing these chemicals should never be used on cats.
Signs of toxicity include tremors, twitching, seizures, loss of coordination, excitability, rapid breathing, weakness, drooling, dilated pupils, vomiting, diarrhea, and loss of appetite. Without prompt, aggressive veterinary care, many cats exposed to pyrethroids die.
My cats often rub against my dogs, so I don’t use pyrethroid pesticides on my dogs. If you choose to do this, allow the product to dry before cuddling or playing with Beauty and Beast; It is even safer to delay contact by 72 hours.
The best way to protect both beauty and the beast is to treat them with products labeled for their respective species. Your vet can prescribe you products that will last months and may be less expensive than the monthly products you are using now.
Q My dog Finn has ingested toxic substances twice. His vet gave him activated charcoal to bind the toxins so they wouldn’t be absorbed and harm him. In this case, can I save myself a trip to the vet by giving Finn ground charcoal?
A Your vet has given you activated charcoal, a medicinal product that binds freshly ingested toxins before they can get into the blood and circulate throughout the body.
Barbecue charcoal is very different from activated charcoal, which is a carbon product that has been treated with oxygen to form a superporous substance with a large surface area for binding toxins.
Even if you have had activated charcoal, you should not give it to your dog as it is contraindicated in certain conditions including dehydration. slowed intestinal motility; gastrointestinal bleeding, obstruction, or perforation; and conditions that predispose the dog to inhaling the product rather than swallowing it.
In addition, it should not be administered after ingesting certain toxins, especially caustic and caustic agents, alcohol, antifreeze, xylitol, petroleum products, fertilizers, most metals and salt, including paintballs and homemade playdough.
Timing of administration is also important, as activated charcoal is only effective when the toxin has not yet been ingested. Some toxins, like drugs, are absorbed quickly, while others, like rodenticides in baits containing grains, are absorbed more slowly.
So your veterinarian is the only person who can determine if and when to administer activated charcoal.
Use your energy to stop Finn from eating things he shouldn’t be eating. If he does, take him to a veterinarian immediately.
Lee Pickett, VMD, practices veterinary medicine in North Carolina. Contact them at