Effective flea and tick control is important since these parasites transmit many diseases, feed off the pet’s blood, and can cause diseases in humans.  All means of flea and tick control can have adverse effects in some situations.

Approximately 70 flea and tick products are registered in the U.S. with the Environmental Protection Agency (EPA).  There are pills, impregnated collars, sprays, dips, shampoos, powders, and "spot-on" products.  Spot-on products are liquids in tubes that are squeezed onto the skin and work primarily on or in the skin.  Spot-ons are applied over the shoulders to prevent the animal from ingesting the product.  

Flea and tick control products should be safe for the animal treated, people and other animals with the treated animal, and the environment.  Reports of adverse effects with spot-on products have increased in the last year.  The reported adverse effects have included skin irritation, skin burns, convulsions, and in up to 2%, death in pets.  Most cases of adverse effects occur in cats.  In April, 2009, the EPA issued an advisory concerning spot-on flea and tick products.  After further investigation, the EPA announced it in June was intensifying the evaluation of spot-on flea and tick products.

Are Spot-On Flea and Tick Products Dangerous?

Potentially yes, but the current evidence is that the vast majority of adverse effects being reported involve over-dosage or the wrong product for the type of animal.  

Overdosage is likely if the animal current weight is guessed and not measured, or if it is erroneously assumed that if a little flea and tick control is good, more is better.   Animals that are weak, aged, on other medications, sick, pregnant, or nursing are more susceptible to spot-on toxicities.   Permethrin is a spot-on medication that is very effective and reasonably safe in dogs, but it causes severe adverse effects in cats.

Proper Use of Flea and Tick Products:

•                     Read labels carefully

•                     Follow directions exactly

•                     Separate treated pets until a spot-on has dried to prevent another animal from licking it

•                     Talk to your veterinarian if planning to treat weak, aged, sick, pregnant, or nursing animals with flea and tick products or if an animal is on other medications

•                     Monitor treated animals carefully after applying flea and tick products

•                     If adverse effects from a spot-on is suspected, bathe it immediately, and call your veterinarian

•                     Use gloves or wash your hands immediately after applying spot-ons

•                     Store flea and tick products away from food preparation areas and out of the reach of children

A Consumers Update is Available at:

http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm169831.htm

For more information, contact your local veterinarian or the MU Veterinary Medical Teaching Hospital 573-882-7821 or visit www.vmth.missouri.edu/