Drug Efficacy of Terbinafine Hydrochloride (Lamisil^®) During Oral Treatment of Cats, Experimentally Infected with Microsporum canis

Abstract

Cats represent a primary source of Microsporum canis infections in humans. Terbinafine hydrochloride (Lamisil) is commonly used in the treatment of microsporosis in humans as its fungicidal action permits short periods of treatment. The aim of the present study was to estimate the efficacy of the drug in cats. Nine cats were experimentally infected with M. canis and treated with terbinafine hydrochloride at a dose of 10-20 mg/kg (once daily, SID; low-dose group, LDG). Another nine cats were similarly infected and treated with 30-40 mg/kg SID (high-dose group, HDG) and a further nine cats were also infected and left untreated (control group, CG). The general condition of the cats was observed daily and their clinical symptoms evaluated weekly. The cats recovery was monitored using the Wood's lamp illumination test and microscopic and fungal culture examinations. The general condition of the cats during the study was good. The cure rates of the LDG were not significantly different from the CG at any period during the treatment. However, the HDG cure rates differed significantly from the other two groups. After 109 days of treatment, when all nine cats of the HDG were healed, seven cats of the LDG and all the cats in the CG were still M. canis-positive. This study shows that dosages of 10-20 mg/kg SID of terbinafine hydrochloride are not sufficient to terminate an experimental M. canis infection in cats within an acceptable period of time. Terbinafine hydrochloride can be used to treat dermatophytosis in cats, but a higher dosage, 30-40 mg/kg SID, should be used to achieve a cure.

Evaluation of persistence of terbinafine in the hair of normal cats after 14 days of daily therapy

“…This study was designed to detect terbinafine concentrations in the hair of cats because dermatophyte infections in animals primarily affect the hair shaft 3 . Although terbinafine is not registered for use in veterinary medicine, it has been successfully used for the treatment of M. canis in several studies 9–13 . The majority of the studies referred here used experimentally infected cats to establish efficacy.…”

“…High efficacy rates and short treatment times in humans are most likely due to the build up of terbinafine at sites of action. Numerous studies have also shown the successful use of this drug in cats with M. canis infections 9–13 …”

Use of lime sulphur and itraconazole to treat shelter cats naturally infected withMicrosporum canisin an annex facility: an open field trial

“…Although it has been documented that the disease is self‐limiting and healthy animals will eventually self‐cure, treatment is recommended for the following reasons: to speed resolution of the infection, to limit the spread of the infection to other susceptible animals and people, and to minimize contamination of the environment 1–4 . There are many successful treatment protocols in the literature involving daily or pulse therapy administration of a systemic antifungal agent accompanied by appropriate laboratory monitoring of complete blood counts and/or chemistry panels, weekly or twice weekly application of topical antifungal solutions, clipping of the hair coat, confinement, and home hygiene recommendations 5–20 . The published protocols involved pet cats, cattery cats, or cats with experimental infections 3,4,6–14 .…”

“…The published protocols involved pet cats, cattery cats, or cats with experimental infections 3,4,6–14 . Current treatment recommendations stem from both in vivo and in vitro studies 3,4,6–16,19,20 …”

Efficacy of Topical Therapy with Newly Developed Terbinafine and Econazole Formulations in the Treatment of Dermatophytosis in Cats

“…After a number of studies in animals, scientists have proved that orally administered terbinafine is effective in the treatment of cats suffering from experimentally induced or naturally occurring dermatophytosis (Castanon-Olivares et al 2001, Kotnik 2002, Kotnik and Cerne 2006, Foust et al 2007). Recently topically applied terbinafine showed superior effectiveness in the treatment of experimental M. canis infection in guinea pigs (Ivaskiene et al 2011).…”