Confirmation of the efficacy of a novel fipronil spot-on for the treatment and control of fleas, ticks and chewing lice on dogs.

A novel spot-on formulation containing fipronil (Eliminall(®)/Exproline vet™) Spot-on Solution for Dogs, Pfizer Animal Health, registered and manufactured by Krka, d.d, Novo mesto) was evaluated in three laboratory studies to confirm efficacy against fleas, ticks and chewing lice on dogs for at least one month. Control of two laboratory strains of cat flea (Ctenocephalides felis), two tick species (Rhipicephalus sanguineus and Dermacentor reticulatus) and the chewing louse (Trichodectes canis) was evaluated. In all studies, dogs were randomly allocated to treatment groups and compared with untreated dogs. The studies also included a commercial, comparator product containing fipronil (Frontline(®) spot-on, Merial Limited). All treatments were applied to the skin at one spot between the scapulae on Day 0. In the studies, dogs were infested with fleas and/or ticks prior to treatment and then reinfested at weekly intervals for up to 8 weeks after treatment and evaluated for efficacy at 2 days (48 h) after treatment and each reinfestation. These studies confirmed that treatment with the novel fipronil spot-on at the proposed commercial dose rate rapidly reduced existing infestations of fleas, ticks and chewing lice on dogs. Treatment provided control of reinfesting fleas for up to 8 weeks, up to 4 weeks control of ticks, and control of chewing lice.

Serum concentrations of methimazole in cats after a single oral dose of controlled-release carbimazole or sugar-coated methimazole (thiamazole).

Methimazole (thiamazole) is an antithyroid drug commonly used to treat feline hyperthyroidism. It is routinely given twice daily. Carbimazole is a methimazole derivative that is rapidly metabolized to methimazole in vivo. A controlled-release tablet for once-daily carbimazole therapy has recently been developed in an attempt to improve compliance during medical management of feline hyperthyroidism. The results of a crossover study in six cats suggest that the pharmacokinetics of methimazole with a single dose of this controlled-release tablet may be similar to those with a single dose of a sugar-coated methimazole tablet when the two drugs are given at an equimolar dose. The mean half-lives were nearly identical (3.12 hours, sugar-coated methimazole tablets; 3.28 hours, controlled-release carbimazole tablets). The serum concentrations of methimazole at 24 hours were 21.7 ± 28.9 ng/mL in the cats treated with 5-mg sugar-coated methimazole tablets and 28.7 ± 37 ng/mL in the cats treated with 10-mg carbimazole tablets (which provide approximately 25% more methimazole after conversion to the active metabolite).