I don’t know about you, but this photo gives me the willies. This is a dog’s fur. The little black specks are flea dirt. Flea dirt is a nice way of saying flea poop. Flea poop contains blood. You can prove this to yourself by placing a few specks on a wet paper towel, which will turn reddish-orange due to the blood. Gross, right? And very uncomfortable for your dog. Not to mention that in the worst flea infestations, a dog can actually become anemic due to these blood-sucking parasites. What’s a dog lover to do?
There are two new FDA-approved products on the market this year for dogs: Nexgard and Bravecto. Nexgard is made by Merial, Bravecto is made by Merck, and they are in the same chemical family. These drugs work by causing uncontrolled activity in the nervous system of fleas and ticks, leading to death. Nexgard was released to the market first, followed by Bravecto. I’d like to help you decide whether either of these products is a good choice for your dog. To do this, I’ll summarize the product insert for you, because it contains the important information you need to know.
Which Dogs Can Take It?
Nexgard: dogs at least 8 weeks of age and weighing at least 4 pounds.
Bravecto: dogs at least 6 months of age and weighing at least 4.4 pounds.
How Do I Give It?
Nexgard: beef-flavored chewable tablet given once each month with or without food. Dosage depends on your dog’s weight; 5 strengths available.
Bravecto: chewable tablet given once every twelve weeks (or every 3 months) with food. *Note that for control of the lone star tick, it must be given every 8 weeks. Dosage depends on your dog’s weight; 5 strengths available.
What Does It Work Against?
Nexgard: Fleas (Ctenocephalides felis); Black-legged tick (Ixodes scapularis); American Dog tick (Dermacentor variabilis); Brown Dog tick (Rhipicephalus sanguineus); and Lone Star tick (Amblyomma americanum).
Bravecto: Fleas (Ctenocephalides felis); Black-legged tick (Ixodes scapularis); American Dog tick (Dermacentor variabilis); Brown Dog tick (Rhipicephalus sanguineus) and Lone Star tick (Amblyomma americanum).
Is It Safe?
Nexgard: in a field study of 415 dogs, reactions included vomiting, dry/flaky skin, diarrhea, lethargy, and lack of appetite. These reactions occurred in 4% or less of dogs. Three dogs in the study had a history of seizures; 2 out of 3 experienced one or more seizures after taking Nexgard. In the margin of safety study, Nexgard was given at 1, 3, and 5x the recommended dose, with only vomiting noted as an adverse event. All lab data collected from all dogs was normal.
Bravecto: in a field study of 294 dogs, reactions included vomiting, decreased appetite, diarrhea, lethargy, and increased drinking. These reactions occurred in 7.1% or less of dogs. In the margin of safety study, Bravecto was given at 1, 3, and 5x the recommended dose, with diarrhea and vomiting noted as adverse events. All lab data collected from all dogs was normal.
To Give or Not to Give?
Most dog owners, given a choice between once monthly and every three month administration, would choose the latter. Nexgard may have its place for dogs under 6 months of age who cannot be started on Bravecto. I’ve been reading through message board posts on Veterinary Information Network, and so far, my colleagues who are prescribing these drugs are happy with how well they’re working and are seeing minimal side effects, in keeping with the data reported by Merial. Although these drugs are new to the U.S. market this year, folks in Europe have been using them for several years with no red flags cropping up.
Pricing for Bravecto is similar to a 3-month supply of Frontline. One veterinarian commented that her own very picky dog, who normally will not eat any flavored tablet, scarfed down her Bravecto with no issue.
Keep in mind that because these drugs are systemic, fleas and ticks WILL get on your dog’s body and must bite to be exposed to the drug. Nexgard and Bravecto will not repel fleas and ticks. However, studies show that within 2-4 hours of administration, Bravecto and Nexgard begin killing existing fleas. Within 48 hours of administration, both kill ticks.
Remember that none of the flea/tick products or methods of control and prevention is 100% effective, 100% of the time. I believe Nexgard and Bravecto are safe and effective choices for most dogs and are a great alternative when topicals and collars are not an option. Have any of you used either of these products? If so, please comment and tell us about your experience! [Added comment 6/3/16: I will not prescribe Nexgard or Bravecto to dogs. After months of communicating with dog owners, reading and researching, it is clear I cannot predict which dog may have side effects from these drugs, and if side effects occur, I cannot remove the drug from the dog’s body.]
This blog post has generated a lot of comments, questions, and unknowns. Thanks to all of you who have read this and posted comments. I’d like to be able to give more information about how these two drugs are performing in the field, both in terms of effectiveness and safety. Unfortunately, the FDA’s website only contains Adverse Drug Event (ADE) reports up to 4/30/13, which means neither Bravecto or Nexgard are included. Today I submitted a Freedom of Information Act request to obtain the ADE reports, so I can give you more information about safety. I’ll post the results as soon as I receive them!
Today I spoke to a Government Information Specialist, who informed me they are working on my FOI request! She said I can expect to receive the ADE reports for Nexgard and Bravecto in 1.5 – 2 weeks. Look for a brand new blog post on this topic after I receive the reports.
I reached out again to the Information Specialist, inquiring when I can expect to receive the ADE reports. She said they’re still working on them and it may take a few more weeks. Sigh. I am impatiently waiting!
***UPDATE*** Links to ADE reports
I’ve closed commenting on this article for now. If you’ve given your dog one of these drugs and he or she has experienced side effects, please reach out for assistance and support at the Bravecto and Nexgard Facebook groups. I strongly urge you to report side effects to the FDA.