The article in our last edition discussed the hidden dangers of fleas and ticks. It mentioned the topical flea and tick products which have become very popular and are now widely available. There is a new chapter in flea and tick control that warrants addressing. The new delivery system is not topical, on the skin but oral, through the mouth. These products are not really so new but more of them are now on the market and they have stood the test of time and safety.
The first oral flea medication came on the market a little over ten years ago. It was called Capstar. The idea behind the medicine was that the active ingredient, nitenpyram, was a neurotoxin that only affects insect nervous systems, not mammalian systems. That is, it would kill the flea in very low doses but even relatively high doses would be safe in animals. This drug was not designed to be long lasting. It only stayed in the animal’s system for a short time so basically, it only killed the fleas which were on the animal the day that the drug was administered. While it was touted as being safe enough to give every day, the expense of daily administration would prohibit its use that way. The patent for Capstar expired this year in April and generic medications with the same active ingredient rapidly hit the market.
Because Capstar only killed the fleas which were present on the day it was administered, its makers, Novartis Animal Health, started looking for a way to make it better. They came up with another medication which could basically sterilize the flea, preventing the hatching out of flea eggs. This would break the life cycle of the flea on the dog or cat and then the Capstar could be used as needed to kill adult fleas. This second product was called Program and the active ingredient was a drug called lufeneron. The concept of sterilizing the flea to decrease the flea population on the dog was a good one. The only problem was that it did not kill adult fleas. Lufeneron is still available as Program and in a combination product that also prevents heartworm and controls some intestinal worms called Sentinel. Sentinel is only available for dogs while Program is available for both dogs and cats.
Sentinel did a pretty good job of flea control for dogs with a controlled environment but the fact that it did not kill adult fleas meant that dogs and cats could still get fleas. Periodic use of Capstar helped but the Capstar had to be given over and over again. In 2008, a new oral flea pill was released that kills fleas for a full month. That product was called Comfortis. A few years later, the active ingredient in Comfortis, called spinosad, was combined with milbemycin, a popular heartworm and intestinal worm preventative, to create the product called Trifexis. Trifexis continues to be one of the most popular heartworm and intestinal worm preventatives because it also kills fleas for a full month. Trifexis is only available for dogs while Comfortis is available for both dogs and cats.
Up until a couple of years ago, the oral parasite killing drugs only attacked fleas, heartworm and intestinal worms. There was no oral medication that killed ticks. That changed with the release of two new drugs around the same time a little over two years ago. Nexgard, a product containing the drug afoxolaner, is a beef flavored chewable that kills both fleas and ticks on dogs for a full month. Another product called Bravecto, containing the active ingredient fluralaner, boasts being able to kill fleas and ticks in dogs for up to 12 weeks. Rumors are that one of these two drugs will soon be combined with one of the heartworm and intestinal worm killers in order to produce a product that can control all of these animal parasites with one monthly pill. So far, the flea and tick pills can only be used in dogs. Cats present a more difficult challenge because they are generally more sensitive to medications so it sometimes takes longer to find a safe medication level for them.
Medication safety is an important issue in our pets. What makes these oral medicines safe to use is the fact that the drugs use target systems in the parasites which are different from these same systems in our pets. Therefore, the drug kills the parasite while having no measurable effect on the pet. While I was as skeptical as any and more skeptical than some when these products first hit the market, the fact that they have been used for years without significant adverse side effects makes me comfortable in recommending them to my patients. Yes, we worry about potential side effects of any medication. But when it comes to fleas and ticks, the hidden dangers of the parasites makes keeping them off of our pets worth the slight risk of the side effects. Flea and tick season is not quite over yet. Ask your vet how you can safeguard your pet with the next generation of flea and tick protection.
Robin N. Brock, D.V.M.
Farmland Veterinary Clinic, P.A.
Farm, Home and Office Calls
336-492-7148 for an appointment
3793 Hwy. 64 West in Mocksville
(located at the intersection of Hwy. 64 and Hwy. 901)
You’ll find Dr. Brock’s pet insights in every issue of Yadkin Valley Living Magazine.