title: The pharmacological effects of the anesthetic alfaxalone after intramuscular administration to dogs.
abstract: The pharmacological effects of the anesthetic alfaxalone were evaluated after intramuscular (IM) administration to 6 healthy beagle dogs. The dogs received three IM doses each of alfaxalone at increasing dose rates of 5 mg/kg (IM5), 7.5 mg/kg (IM7.5) and 10 mg/kg (IM10) every other day. Anesthetic effect was subjectively evaluated by using an ordinal scoring system to determine the degree of neuro-depression and the quality of anesthetic induction and recovery from anesthesia. Cardiorespiratory variables were measured using noninvasive methods. Alfaxalone administered IM produced dose-dependent neuro-depression and lateral recumbency (i.e., 36 ± 28 min, 87 ± 26 min and 115 ± 29 min after the IM5, IM7.5 and IM10 treatments, respectively). The endotracheal tube was tolerated in all dogs for 46 ± 20 and 58 ± 21 min after the IM7.5 and IM10 treatments, respectively. It was not possible to place endotracheal tubes in 5 of the 6 dogs after the IM5 treatment. Most cardiorespiratory variables remained within clinically acceptable ranges, but hypoxemia was observed by pulse oximetry for 5 to 10 min in 2 dogs receiving the IM10 treatment. Dose-dependent decreases in rectal temperature, respiratory rate and arterial blood pressure also occurred. The quality of recovery was considered satisfactory in all dogs receiving each treatment; all the dog exhibited transient muscular tremors and staggering gait. In conclusion, IM alfaxalone produced a dose-dependent anesthetic effect with relatively mild cardiorespiratory depression in dogs. However, hypoxemia may occur at higher IM doses of alfaxalone.
authors.affiliation: Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Tamura
authors.forename: Tomohito
authors.initials: T
authors.lastname: Ishizuka
authors.forename: Sho
authors.initials: S
authors.lastname: Fukui
authors.forename: Norihiko
authors.initials: N
authors.lastname: Oyama
authors.forename: Kodai
authors.initials: K
authors.lastname: Kawase
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Miyoshi
authors.forename: Tadashi
authors.initials: T
authors.lastname: Sano
authors.forename: Kirby
authors.initials: K
authors.lastname: Pasloske
authors.forename: Kazuto
authors.initials: K
authors.lastname: Yamashita
mesh_terms: D000777:Anesthetics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure; D001831:Body Temperature; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000662:veterinary; D005260:Female; D006339:Heart Rate; D007273:Injections, Intramuscular; D008297:Male; D010100:Oxygen / Q000097:blood; D011277:Pregnanediones / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000777:Anesthetics; D011277:Pregnanediones; C006477:alphaxalone; D010100:Oxygen