Which alpha-adrenergic blocking agent is used as a reversal for xylazine? Trade Yobine.

• A. Tolazoline
• B. Yohimbine
• C. Naloxone
• D. Atipamezole

Answer: (B)

Xylazine produces its sedative and analgesic effects by stimulating alpha-2 adrenergic receptors, so reversing its action requires an antagonist that blocks those receptors. Yohimbine is an alpha-2 adrenergic antagonist, and when given (sold under the trade name Yobine in many markets) it competes with xylazine at the receptor, allowing sympathetic activity to resume and the animal to recover from sedation more quickly. This is why Yohimbine is the correct reversal in this context. Be aware that reversing xylazine can cause rapid increases in heart rate and blood pressure, and in some animals may lead to agitation. Modern practice often favors a more selective agent like atipamezole for predictable reversal, but the trade name Yobine refers to Yohimbine.