Canine generalized demodicosis treated with varying doses of a 2.5% moxidectin+10% imidacloprid spot-on and oral ivermectin: parasiticidal effects and long-term treatment outcomes.

Advocate(®) (2.5% moxidectin+10% imidacloprid) (Bayer HealthCare, Leverkusen, Germany) is a multiparasiticidal spot-on authorized for treating canine demodicosis in many countries. This blinded, randomized three-phase clinical trial compared its efficacy employing different dosing regimens with that of ivermectin. In the blinded first phase, 58 dogs suffering from generalized demodicosis were randomly assigned to one of four groups and treated with monthly, biweekly or weekly applications of Advocate(®), or with oral ivermectin (IVR) at 500 µg/kg daily. Dogs were evaluated clinically and multiple skin scrapings undertaken every 4 weeks until parasitological cure was achieved (defined as two consecutive series of deep skin scrapings at monthly intervals negative for all life forms). Forty dogs completed the 16-week initial blinded phase, with 5 cases achieving parasitological cure. Five dogs were deemed treatment failures and subsequently treated with ivermectin. The treatment protocol was then changed for the remaining 35 dogs and this cross-over phase (Phase 2) was maintained for a further 8 weeks with an additional 9 dogs achieving parasitological cure. Thereafter, all remaining animals were treated with IVR until cured (Phase 3). Overall, 26 dogs achieved parasitological cure during the clinical investigation. Of these, 23 remained disease-free for at least 12 months while two were lost to follow up and one died of unrelated causes. A total of 32 (55.2%) dogs were withdrawn at various stages of the investigation including the 5 dogs that were judged treatment failures. Other reasons for withdrawal included: non-compliance, lost to follow-up, ivermectin toxicity or reasons unrelated to the investigation. No adverse effects were attributable to the use of Advocate(®). Parasiticidal efficacy was assessed by changes in mite counts (live adult, juvenile and egg) and skin lesion extent & severity scores. Statistical significance was assessed using ANCOVA with initial mite counts or skin scores used as the covariate to account for variations in disease severity. Planned pairwise comparisons were used to identify differences between treatment groups. The efficacy of Advocate(®) increased with its rate of application across all measures of efficacy. Although ivermectin was shown to be more effective than Advocate(®) applied once weekly, both treatment protocols produced clinically satisfactory results. It was concluded that weekly application of Advocate(®) can be recommended as effective for the treatment of canine generalized demodicosis without the potential for toxicity associated with ivermectin.

Treatment of canine-generalized demodicosis: a blind, randomized clinical trial comparing the efficacy of Advocate(Bayer Animal Health) with ivermectin.

Advocate (moxidectin 2.5% + imidacloprid 10%) is a multiparasiticidal agent authorized for treating canine demodicosis in many countries. This blind, randomized clinical trial assessed the efficacy of Advocate at varying treatment intervals and compared it with that of oral ivermectin. Fifty dogs with generalized demodicosis were randomly assigned to one of four treatment groups: oral ivermectin (500 microg/kg once daily), Advocate applied at the authorized dose monthly (ADV1), every 2 weeks (ADV2) or weekly (ADV4). Each dog was evaluated every 4 weeks for 4 months or until negative scrapings at all sites resulted on two successive evaluations (parasitological cure). Miticidal efficacy was determined through deep skin scrapings taken from the same three sites on each occasion. Total numbers of live and dead adult mites, juveniles and eggs were determined. Thirty-five dogs completed the 4-month trial. Parasiticidal efficacy was assessed using several parameters including reduction in live adult mite counts. ancova analysis for this parameter confirmed that there were differences in efficacy among the treatment groups (P < 0.002). Tukey-Kramer all pairwise multiple comparison tests revealed that ADV4 was more effective than ADV1 (P = 0.016). Ivermectin was more effective than ADV1 (P = 0.003). Both ivermectin and ADV4 showed clinically substantial reductions in adult mite counts (89% for ADV4 and 98% for ivermectin). In conclusion, the efficacy of Advocate increased with the rate of application and weekly application may represent a new approach to the treatment of caninegeneralized demodicosis.