Assessment of the onset of lotilaner (Credelio™) speed of kill of fleas on dogs

Abstract

BackgroundLotilaner (Credelio™) is the newest member of the novel isoxazoline chemical class to be developed to treat canine ectoparasitism. Administered orally, lotilaner is rapidly absorbed with peak blood levels occurring within 2 h post-treatment. A study was undertaken to determine the earliest onset of lotilaner’s efficacy against existing flea infestations.MethodsFrom 72 Beagles, 64 qualifying dogs were ranked in descending order of flea counts from a Day -8 infestation and placed into eight blocks. Within blocks, eight dogs were randomly allocated among eight groups: Groups 1 to 4 were treated orally with lotilaner, at as close as possible to the minimum dose rate of 20 mg/kg within 30 (± 5) minutes after feeding; Groups 5 to 8 were untreated controls. All dogs were infested with 100 ± 5 fleas on Day -2, and whole-body flea counts were completed at 30 min and one, two and 8 h after treatment. Efficacy calculations were based on arithmetic and geometric means if an adequate infestation (at least six of eight untreated dogs with a flea retention of ≥ 50%) was demonstrated in the equivalent control group.ResultsAdequate infestations were established in all control groups. At 30 min and 1 h post-treatment, relative to the matching untreated control group, there were no significant reductions in mean flea counts in lotilaner-treated dogs, although moribund fleas were evident at 1 h post-treatment. At 2 h after treatment, compared with the equivalent control group, the geometric mean flea count reduction in the lotilaner group was 64.0% (t (7) = 2.86, P = 0.0242). At 8 h after treatment, lotilaner efficacy was 99.6%. There were no treatment-related adverse events.ConclusionThis study demonstrates that lotilaner flavored chewable tablets are well tolerated and begin to kill fleas within 2 h of treatment, achieving 99.6% efficacy within 8 h. Lotilaner can therefore be used to quickly alleviate the flea irritation that arises from existing infestations.Electronic supplementary materialThe online version of this article (10.1186/s13071-017-2474-0) contains supplementary material, which is available to authorized users.

Canine flea control: too much choice?

“…While all four products are known to have rapid SOKs, sarolaner appears to be the most effective on the basis of this work by Six (Six et al, 2016b;2016c;2016d). The most recent of the isoxazolines, lotilaner, has also been shown to have a rapid SOK and to maintain its efficacy between applications (Cavalleri et al, 2017b;2017c). It has also been shown to start killing fleas within 2 hours (Rust and Hemsarth, 2019).…”

Efficacy of lotilaner (Credelio™) against the adult cat flea, Ctenocephalides felis and flea eggs following oral administration to dogs

“…At 6 h post-treatment/infestation, efficacy against adult fleas was > 99% for up to 35 days [13]. The rapid onset of lotilaner was further shown in a speed of kill study using C. felis, where at 1 h post-dosing 22 moribund fleas were collected from five lotilaner treated dogs compared to one moribund flea from a single dog in the control group [11]. A moribund flea was a flea that was laterally recumbent; could not normally move through hair or right itself when placed on a flat surface but still had leg movement or twitching.…”

“…A pharmacokinetic study has shown that, when administered with food, lotilaner is rapidly absorbed, with peak plasma concentrations occurring within approximately 2 h following oral administration, and a half-life of approximately 30 days [10]. The rapid absorption of lotilaner translates into a rapid onset of activity against fleas with laboratory studies showing lotilaner begins killing fleas and ticks within 4 h after treatment [11,12]. Efficacy against fleas and ticks was then sustained through 35 days after a single treatment, indicating that monthly use of lotilaner is effective in reducing the flea life-cycle stages in a dog's environment [13].…”

Recent Advancements in the Control of Cat Fleas

“…Several studies have been conducted to determine the speed at which fleas are killed by lotilaner. In a laboratory study with dogs with existing infestations of C. f. felis , lotilaner provided 64 and 99.6% reductions in the number of fleas counted at 2 and 8 h, respectively [ 61 ]. An oral dose of lotilaner to dogs provided 89.9% kill of existing cat flea infestations at 4 h and 100% kill at 12 h. When treated, dogs were challenged with adult fleas for up to 35 days, there was >97% kill at 4 h [ 62 ].…”