Since last spring, the EPA has been looking into the ingredients in spot-on flea and tick medications, prompted by a surge in reports of adverse reactions among pets dosed with these products.

In a summary 3/16/10, the EPA cited that the products can be effective, but cautioned consumers when applying, particularly to small dogs and cats. Consumers were also advised to consult their veterinarian.

The EPA emphasized that most of the reported problems in pets were mild, and many adverse reactions were caused by misuse (such as applying a dog dose on a cat).

However, small dogs were most affected.

Among product concerns expressed by the EPA were these:

Confusing or ineffective label warnings.
Gaps in safety testing.
Dose ranges that may be too broad for the weight variations in small dogs.

The EPA's Web site recommends "that owners consult a veterinarian about the best way to protect their pets from fleas and ticks or whether pesticides are needed, especially before using any product on weak, aged, medicated, sick, pregnant or nursing pets, or on pets that have previously shown signs of sensitivity to pesticide products."

Consumers were also warned of counterfeit versions. The EPA website has a list of registered spot-ons. Click here to view   EPA registered flea and tick products   Consumers should check the product registration number on the list against the product registration number on the box to verify. 

The EPA also announced last week that it will "develop more stringent testing and evaluation requirements for both existing and new products" and encouraged pet owners to carefully read and follow all labeling instructions before applying pesticides on pets.

The EPA plans to pursue restrictions on certain inert ingredients suspected of contributing to side effects; an information campaign to "help users avoid making medication errors"; and requirements for better reporting of "adverse effects."