NexGard Approval Extended to Lyme Disease Prevention

July 18, 2018
American Veterinarian Staff

The chewable tablet is now FDA approved for the prevention of Borrelia burgdorferi infections.

The FDA has extended the label for NexGard (afoxolaner, Merial) to include prevention of Borrelia burgdorferi infections in dogs. The drug works by killing black-legged ticks—Ixodes scapularis—which carry the bacterium.

An estimated 5% to 10% of dogs exposed to B burgdorferi develop Lyme disease.


  • Blocking Vector-Borne Disease in Humans With Veterinary Parasiticides
  • Developing a Vaccine for Lyme Disease

NexGard, a chewable for dogs, was approved by the FDA in 2013 to treat and prevent flea (Ctenocephalides felis) infestations and to treat and control black-legged tick, American dog tick (Dermacentor variabilis), Lone Star tick (Amblyomma americanum), and brown dog tick (Rhipicephalus sanguineus) infestations in dogs and puppies 8 weeks of age and older, weighing at least 4 lb. Each chewable provides 1 month of protection.

The data presented by Merial in the supplemental application demonstrated that the transmission of B burgdorferi after exposure to infected ticks was prevented as a direct result of Nexgard killing the ticks.

For more information, visit the NexGard website.