Loxodonta africana are susceptible to a wide variety of parasites that are often treated with the broad spectrum antiparasitic ivermectin (IVM) based on empirical knowledge. The objectives of this study were to 1) measure plasma IVM levels following administration of 0.1 mg/kg IVM p.o., 2) compare plasma IVM levels following administration with regular versus restricted feed rations, 3) measure IVM excretion in feces, and 4) use these findings to generate dosing recommendations for this species. Using a crossover design, six African elephants were divided into two groups. Ivermectin was administered and typical grain rations were either provided or withheld for 2 hr. Blood and fecal samples were collected for 7 days following drug administration. After a 5-wk washout period, groups were switched and the procedure repeated. Plasma and fecal IVM were analyzed using high-performance liquid chromatography. There was no statistically significant difference detected in the pharmacokinetic data between the fed and fasted groups. Peak plasma concentration, area under the curve, and half-life for plasma ranged between 5.41–8.49 ng/ml, 17.1–20.3 ng × day/ml, and 3.12–4.47 day, respectively. High IVM concentrations were detected in feces. The peak concentration values in feces were between 264–311-fold higher than those obtained in plasma. The comparatively large area under the curve and short time to maximum concentration in feces indicate elimination prior to absorption of much of the drug. Plasma IVM concentrations were low when compared to other species. Based on these findings, administration of 0.2–0.4 mg/kg p.o. should be appropriate for eliminating many types of parasites in elephants, and could minimize development of parasite resistance.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 40 • No. 1