Veterinarians should warn clients that pets can be harmed by ingesting pseudoephedrine.

"Pseudoephedrine has a very narrow margin of safety in dogs, cats, and other animals," says Dr. Steve Hansen, senior vice president of the ASPCA Animal Poison Control Center, which has issued the warning.

Pseudoephedrine is found in certain cold, allergy, and sinus medications used in humans. As little as one tablet containing 30 mg of pseudoephedrine can induce clinical signs in a 20-pound dog, including nervousness, hyperactivity, and other behavioral changes; panting; fast heart rate; and high blood pressure. A dose as small as three 30-mg tablets in the same size dog can be lethal.

"Clinical effects can sometimes be seen as quickly as within 30 minutes after ingestion," Dr. Hansen says. "Therefore, it is critical that veterinary treatment is sought quickly when an ingestion occurs."

As with most medications, animal exposures to pseudoephedrine products usually are accidental, such as a pet chewing into a medication bottle or ingesting pills left unattended. Others may occur as a result of pet owners inappropriately medicating their pets.

Pseudoephedrine and other medications should be kept out of the reach of animals, preferably in a secure cabinet above the counter, according to the poison control center. "It is very important for owners to understand that even childproof containers are not effective in preventing accidental drug exposures in pets, as dogs and other animals can easily chew open a bottle or vial," Dr. Hansen says.

Individuals who suspect a pet may have ingested a pseudoephedrine-containing product or other drug should contact their local veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 for immediate assistance.