Vatinoxan alone increases cardiac index and tissue oxygen delivery and has no deleterious adverse effects. Vatinoxan attenuates or prevents dexmedetomidine’s systemic hemodynamic effects in a dose-dependent manner when given simultaneously i.v. but has no effect on the pulmonary outcome in conscious dogs. A 50:1 dose ratio (Vatinoxan:dexmedetomidine) induces the least alterations in cardiovascular function. Vatinoxan dose-dependently attenuates the bradycardia associated with dexmedetomidine, and shortens the sedative effect without altering its quality. Vatinoxan may be useful in attenuating reductions in heart rate in conscious catsadministered dexmedetomidine.