ATCvet code: QP53AX15
Pharmacodynamics
Fipronil exhibits insecticidal and acaricidal activity against fleas (Ctenocephalides spp.), ticks (Rhipicephalus spp. Ixodes spp.) and lice (Trichodectes spp. and Felicola spp.) in the dog and cat.
Fipronil is a member of the phenylpyrazole family of broad spectrum, non-systemic, insecticides/acaricides, which acts by blocking the GABA receptor to kill the target parasite on contact. The product may aid in the control of a number of ectoparasite species in dogs and cats, including Neotrombicula autumnalis, Sarcoptes spp. and Cheyletiella spp. Treatment with the product has been shown to result in a significant reduction in the incidence of flea allergy dermatitis in both dogs and cats. When used as part of a strategy for the treatment of flea allergy dermatitis, monthly applications to the allergic patient and to other cats and dogs in the household are recommended.
Pharmacokinetics
+ Absorption
The amount of fipronil absorbed by the skin in the dog, after application of the spray to the coat and skin is extremely slight to negligible.
+ Distribution
The persistence of fipronil on the hair is very long (on average 52.5 ± 11.5 days), given that the limit of quantification of the assay method is 0.25 µg/g.
+ Biotransformation
In all species fipronil is mainly metabolised to its sulphone derivative (RM1602), which also possesses insecticidal and acaricidal properties.
The RM1602 detected on the hair after spray application in dogs may be explained by its presence in the original raw material.