NexGard Spectra (afoxolaner & milbemycin oxime) is a monthly chewable tablet for dogs that provides broad-spectrum parasite protection. Protects against fleas, ticks, mites, lungworm, and roundworms. It also offers heartworm prevention and treats gastrointestinal nematode infestations. The active ingredients, afoxolaner and milbemycin oxime, work by disrupting the nervous systems of the parasites. Contains afoxolaner, which is a member of the isoxazoline class.