Effipro spot on for large dogs for the treatment of flea ctenocephalides spp and tick dermacentor reticulatus infestations insecticidal efficacy against new infestations with adult fleas persists for up to 8 weeks the product has a persistent acaricidal efficacy for up to 4 weeks against ticks rhipicephalus sanguineus ixodes ricinus dermacentor reticulatus if ticks of some species rhipicephalus sanguineus and ixodes ricinus are present when the product is applied all the ticks may