Exactly How Effective are Traditional Flea & Tick Medications at Controlling Ticks?
Updated: Jul 8, 2019
I’ve noticed that every time I turn on the TV lately I see an advertisement for at least one of the traditional flea and tick medicines that veterinarians routinely prescribe. The newer medications that are given in pill form vs. a topical have been touted by manufacturers as more effective, easier to use, and having less chance of accidental human exposure.
However, in light of the FDA’s recent alert about the isoxazoline class of flea and tick medications consumers are becoming more and more leery and are looking for more natural alternatives to rid their beloved dogs and cats of fleas and ticks. I am a member of at least 10 Facebook groups about dogs and I can’t even begin to count the number of posts I’ve seen about people searching for a natural approach that “works” particularly when it comes to ticks. It seems as though people are looking for 100% protection against one of nature's most versatile, resilient creepy crawly insects...the tick. They want something that works 100% of the time to kill or repel ticks without using any potentially toxic chemicals.
The posts I’ve seen about using something natural and then finding a tick in a house, on a person, or a dog made me wonder. Exactly how effective against ticks are the traditional medications people are trying to avoid and are we expecting the impossible out of a more natural alternative?
With that in mind, I decided to check out the package insert/label for 3 of the most commonly prescribed oral flea and tick medications NexGard, Simparica, and Bravecto (all are members of the isoxazoline class and included in the recent FDA warning about potential neurologic adverse events referenced above). It is important to note that none of these medications repels ticks. They work systemically, so the tick must actually bite your dog or cat before the medication can work to kill it.
NexGuard - Here is a link to the package insert for NexGard from the manufacturer’s website. In the Effectiveness section of the label it states “In well-controlled laboratory studies, NexGard demonstrated >97% effectiveness against Dermacentor variabilis, >94% effectiveness against Ixodes scapularis, and >93% effectiveness against Rhipicephalus sanguineus, 48 hours post-infestation for 30 days. At 72 hours post- infestation, NexGard demonstrated >97% effectiveness against Amblyomma americanum for 30 days.” A couple of things stand out here...first regardless of the type of tick NexGard which touts itself “THE #1 CHOICE OF VETS” is not 100% effective against any type of tick and second that this is after feasting on dogs for 48 hours.
Simparica - Here is a link to the package insert for Simparica from the manufacturer’s website. In the Effectiveness section of the label is states “In well-controlled laboratory studies, Simparica demonstrated >or= to 99% effectiveness against an initial infestation of Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, Ixodes scapularis, and Rhipicephalus sanguineus 48 hours post-administration and maintained >96% effectiveness 48 hours post re-infestation for 30 days." This agent seems to perform a little better, but it still does not work 100% of the time and the tick still has to feast on your dog for 48 hours before it will work.
Bravecto - Here is a link to the package insert for Bravecto from the manufacturer’s website. In the Effectiveness section of the label it states “In well- controlled laboratory studies, Bravecto demonstrated ≥93% effectiveness against Dermacentor variabilis, Ixodes scapularis and Rhipicephalus sanguineus ticks 48 hours post-infestation for 12 weeks. Bravecto demonstrated ≥90% effectiveness against Amblyomma americanum 72 hours post-infestation for 8 weeks, but failed to demonstrate ≥90% effectiveness beyond 8 weeks”.
So there you have it folks. None of these medications is 100% effective against ticks and do nothing to actually repel the nasty little critters. There is nothing to stop a tick from jumping on your dog or cat and then jump ship in your house or on you before it decides to make a meal of them and die 48 hours later. Here is a great article from Popular Science that explains why keeping them off you and your pets is such a challenge. Ticks have a super sensitive sensory organ that smells both carbon dioxide and ammonia and when they get a whiff of either they literally run towards it on their little legs with their front legs outstretched hoping to latch on to whatever emitted that smell. For your pet that means that every breath they take or pee they make the ticks will be waiting.
With that in mind it’s easy to see why it’s probably a little unrealistic to expect even the most effective natural prevention methods to be 100% effective. That’s while you see most sites suggesting a multifaceted approach. Let’s face it, even the chemical laden pills available aren’t 100% effective.