Evaluation of plasma concentration after intravenous and intramuscular penicillin administration over 24 hr in healthy adult horses. Issue 2 (1st November 2018)

• Record Type: Journal Article
• Authors: Younkin, Jarrod T.; Santschi, Elizabeth M.; Kukanich, Butch; Lubbers, Brian V.; Warner, Matthew
• Is Part Of: Journal of veterinary pharmacology and therapeutics. Volume 42:Issue 2(2019)
• Page Start: 239
• Page End: 242
• Publication Date: 2018-11-01
• Subjects: horse -- penicillin -- plasma concentration -- routes; Veterinary pharmacology -- Periodicals; Therapeutics -- Periodicals; 636.0895105
• DOI: 10.1111/jvp.12730
• Languages: English
• ISSNs: 0140-7783

Abstract

Abstract: Penicillin is administered intravenously (IV) or intramuscularly (IM) to horses for the prevention and treatment of infections, and both routes have disadvantages. To minimize these shortcomings, a 24‐hr hybrid administration protocol (HPP) was developed. Our objective was to determine penicillin plasma concentrations in horses administered via HPP. Venous blood was collected from seven healthy horses administered IV potassium penicillin G at 0 and 6 hr and IM procaine penicillin G at 12 hr. Blood was collected at 2‐hr intervals from 0 to 20 hr and at 24 hr. Plasma penicillin concentrations were measured using liquid chromatography and mass spectrometry. Penicillin susceptibility from equine isolates was examined to determine pharmacodynamic targets. The MIC90 of penicillin for 264 isolates of Streptococcus sp. was ≤0.06 μg/ml. For the 24‐hr dosing interval, the mean plasma penicillin concentration was >0.07 μg/ml. Five horses (72%) exceeded 0.06 μg/ml for 98% of the dosing interval, and two horses exceeded this value for 52%–65% of the dosing interval. The HPP achieved mean plasma penicillin concentrations in healthy adult horses above 0.07 μg/ml for a 24‐hr dosing interval. However, individual variations in plasma concentrations were apparent and deserve future clinical study.