McNeel S V, Hsu W H
J Am Vet Med Assoc. 1984 Oct 15;185(8):878-81.
The effects of yohimbine and doxapram on xylazine-induced prolongation of gastroduodenal transit of barium sulfate were studied in 5 dogs. Base-line transit time was determined while the dogs were non-sedated and undisturbed; the time for barium sulfate to move from the stomach to the duodenojejunal junction was 5.6 +/- 4.0 minutes (mean +/- SD). An IV injection of xylazine (1 mg/kg) prolonged the transit time to 95.0 +/- 14.6 minutes. During the xylazine-induced prolongation of gastroduodenal transit, there were no vigorous gastric or intestinal peristaltic contractions for at least 60 minutes. Yohimbine, an alpha 2-adrenergic blocking agent, given IV at a dosage of 0.1 mg/kg, reversed the gastrointestinal and sedative effects of xylazine. Doxapram hydrochloride, an analeptic, given IV at a dosage of 5.5 mg/kg, prolonged the transit time to 43.0 +/- 22.8 minutes. When doxapram was given in combination with xylazine, it potentiated the gastrointestinal effect of xylazine, and further prolonged the transit time to 148.0 +/- 32.7 minutes. It was concluded that yohimbine is effective as an antidote to reverse the xylazine-induced prolongation of gastrointestinal transit, whereas doxapram has no value in this respect.
