Described herein are lifesaving compositions and methods including the administration of alpha-2 (α2)
adrenergic antagonists as a
drug class for use in the reversal of substance overdose that can be contributed to by xylazine and xylazine congeners,
alcohol,
fentanyl / opioids, and benzodiazepines in humans. In some instances, the substance overdoses can appear to be
opioid induced but are not responsive to administration of therapeutic agents (e.g., Naloxone administration). The antagonists can be safely and quickly produced using
yohimbine, and the compositions and methods are operative to address the United States' national crisis of human overdoses caused by combining various illicit (street) drugs with xylazine.