Supplementary file 7_The effects of fentanyl and dexmedetomidine on cardiorespiratory activity: implications for morbidity and mortality associated with adulterated fentanyl products.pdf

The purpose of this study was to examine the effects of fentanyl and the α₂-adrenergic agonist, dexmedetomidine, on cardiorespiratory measures that may contribute to the toxicity of these drug combinations (i.e., respiratory rate, heart rate, oxygen (O₂) saturation, and pulse distention).</p>Methods<p>Male and female rats were administered fentanyl (0.01–0.1 mg/kg) and dexmedetomidine (0.003–0.01 mg/kg) intravenously, and pulse oximetry was used to measure respiratory and cardiovascular activity.</p>Results<p>When administered alone, both drugs decreased respiratory rate and heart rate relative to baseline, albeit with different time courses.

Fentanyl, but not dexmedetomidine, decreased O₂ saturation. Dexmedetomidine enhanced the suppression of respiratory rate and heart rate produced by fentanyl in a time-dependent manner. The effects of the drug combination on O₂ saturation and pulse distention were less consistent.