Hi Dr. Barchas,
Anne, El Campo, TX
In the last several years, only a couple of my patients have had adverse reactions to these products. And the reactions have been mild. Animals sometimes lose hair at the spot where the product is applied. If Advantage is applied improperly to a cat and she gets it into her mouth, she may salivate and become nauseated from the taste.
Although reactions to Advantage and Frontline are rare and generally mild, the same cannot be said about reactions to fleas. Among my patients, fleas are without a doubt the most common and most bothersome pest. Fleas can cause terrible itching, skin rashes, and hair loss. They spread diseases such as tapeworms and cat scratch fever (which can then spread to people). They are thought to contribute to mouth ulcers, asthma, autoimmune disease, allergies, and just about every skin condition imaginable. Fleas can cause anemia. I have even seen pets die from extreme flea infestations.
So, although Advantage and Frontline are not perfect, I believe that they’re much safer than the alternative: fleas.