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Abstract

Objective

To compare pharmacokinetics of eltenac after first and last IV administrations (0.5 mg/kg), using a multiple dosing schedule.

Animals

6 adult mares.

Procedure

Eltenac (50 mg/ml) was administered IV at a dosage of 0.5 mg/kg of body weight every 24 hours for days 0 through 4. On days 0 and 4, blood samples were collected before, then periodically for 8 hours after eltanac administration. Concentration of eltenac in plasma samples was determined by use of high-performance liquid chromatography.

Results

On day 0, median area under the plasma eltenac concentration versus time curve (AUC) was 6.77 μg•h/ml (range, 5.61 to 8.08 μg•h/ml), median plasma clearance was 1.23 ml/min/kg (range, 1.03 to 1.40 ml/min/kg), and median steady-state volume of distribution was 191 ml/kg (range, 178 to 218 ml/kg). Median terminal half-life of eltenac was 2.36 hours (range, 2.30 to 2.98 hours). On day 4, median eltenac AUC was 6.70 μg•h/ml (range, 5.21 to 7.44 μg•h/ml), median plasma clearance was 1.23 ml/min/kg (range, 1.12 to 1.53 ml/min/kg), and median steady-state volume of distribution was 193 ml/kg (range, 172 to 205 ml/kg). Median terminal half-life of eltenac was 2.40 hours (range, 2.11 to 3.25 hours). Protein binding of eltenac, determined by ultrafiltration, was > 99% at a total plasma concentration of 36 μg/ml.

Conclusion

Pharmacokinetic variables determined for each horse were not different between days 0 and 4.

Clinical Relevance

Under conditions of this study, there was no clinically relevant accumulation of eltenac in equine plasma or alteration of pharmacokinetic variables after multiple IV dosing of 0.5 mg/kg of eltenac. (Am J Vet Res 1998;59:1447–1450)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To assess the nematocidal efficacy of eprinomectin in naturally infected cattle.

Animals

62 (31 eprinomectin-treated and 31 control) beef mixed-breed or Holstein cattle, either 6 to 11 or 48 to 96 months old.

Procedure

Cattle were housed 21 to 27 days before treatment to allow parasites to reach maturity. Animals were grouped by sex, ranked by weight, and randomly assigned to treatment group. Fecal flotation was done to identify cattle with intestinal nematode infections. Treatment groups were: 1—eprinomectin topical vehicle (1 ml/10 kg) and 2—eprinomectin topical solution (1 ml/10 kg). Cattle were euthanatized by replicate on day 14 or 15, and standard procedures were used to recover of pulmonary, abomasal, small intestinal, and large intestinal nematodes.

Results

Eprinomectin efficacy across all trials was 100% against adult Trichostrongylus axei, Haemonchus placei, Oesophagostomum radiatum, and Dictyocaulus viviparus, as well as fourth-stage larval Oes radiatum, Ostertagia ostertagi, Nematodirus helvetianus, and Cooperia spp. Efficacy against adult O ostertagi, Cooperia oncophora, C punctata, C surnabada, C spatulata, N helvetianus, Trichuris sp, and Trichuris fourth-stage larvae was 99.9, 99.8, 99.6, 98.9, 98.3, 99.7, 97.8, and 84.3%, respectively. All results were significant (P < 0.01) except those for C spatulata. Adverse reactions were not observed.

Conclusion and Clinical Relevance

Eprinomectin is a safe and effective nematocide against naturally acquired nematode infections in cattle when administered at a dosage of 500 μg/kg. Milk and meat withholding is not necessary when using this product. (Am J Vet Res 1997;58:612–614)

Free access
in American Journal of Veterinary Research