Abstract |
The effects of xylazine on heart rate (HR) and mean arterial blood pressure (ABP) were studied in 5 conscious male dogs. An IV injection of xylazine (1 mg/kg) caused a decrease in HR, which was accompanied by sinus arrhythmia. Xylazine administration also caused an initial increase in ABP, which was followed by a decrease. Atropine sulfate (0.045 mg/kg, IM) increased both the ABP and HR, but prevented xylazine-induced bradycardia only in 3 of 5 dogs. The other 2 dogs had to be given a supplemental dose of atropine sulfate (0.01 mg/kg, IV) before xylazine-induced bradycardia was antagonized. In addition, atropine sulfate potentiated xylazine-induced hypertension for 60 minutes. Yohimbine, an alpha 2-adrenoreceptor blocking agent, given IV at a dosage of 0.1 mg/kg, antagonized hypertension, hypotension, and bradycardia induced by xylazine. In addition, doxapram HCl, given IV at a dosage of 5.5 mg/kg, antagonized bradycardia but potentiated xylazine-induced hypertension, and an IV injection of 4-aminopyridine at a dosage of 0.5 mg/kg did not affect the cardiovascular actions of xylazine. It was concluded that atropine sulfate at the IM dosage of 0.045 mg/kg may be insufficient to antagonize xylazine-induced bradycardia but may potentiate xylazine-induced hypertension, and yohimbine may be useful in antagonizing these untoward reactions associated with xylazine administration. Doxapram and 4-aminopyridine were not found to be beneficial.
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Authors | W H Hsu, Z X Lu, F B Hembrough |
Journal | Journal of the American Veterinary Medical Association
(J Am Vet Med Assoc)
Vol. 186
Issue 2
Pg. 153-6
(Jan 15 1985)
ISSN: 0003-1488 [Print] United States |
PMID | 2857705
(Publication Type: Journal Article)
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Chemical References |
- Aminopyridines
- Central Nervous System Stimulants
- Thiazines
- Xylazine
- Yohimbine
- Atropine
- Doxapram
- 4-Aminopyridine
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Topics |
- 4-Aminopyridine
- Aminopyridines
(pharmacology)
- Animals
- Atropine
(pharmacology)
- Blood Pressure
(drug effects)
- Central Nervous System Stimulants
(pharmacology)
- Dogs
(physiology)
- Doxapram
(pharmacology)
- Drug Interactions
- Heart Rate
(drug effects)
- Male
- Thiazines
(pharmacology)
- Xylazine
(pharmacology)
- Yohimbine
(pharmacology)
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