Use: Afoxolaner chewable tablets (NexGard®) are approved by FDA for the treatment and prevention of flea infestations (Ctenocephalides felis), and the treatment and control of American dog tick (Dermacentor variabilis, also called wood tick), black-legged tick (Ixodes scapularis, also called deer tick), Lone star tick (Amblyomma americanum), and brown dog tick (Rhipicephalus sanguineus) infestations in dogs and puppies 8 weeks of age and older, weighing 4 pounds of body weight or greater, for 1 month.
Side effects: While experience is very limited at the time of writing (2013), in pre-approval field studies (415 dogs over 90 days) serious adverse effects were not noted, although two dogs with a history of seizures had a seizure during the study (causation could not be determined), hence the caution above. The most prevalent adverse effect noted was vomiting (4.1%). Other adverse effects reported (>1%) included dry flaky skin (3.1%), diarrhea (3.1%), lethargy (1.7%) and anorexia (1.2%).