Ketorolac Does Not Decrease the MAC of Halothane or Depress Ventilation in Rats

To determine the effects of intravenous (IV) ketorolac on anesthesia and the mechanisms involved, we evaluated its effects on minimum alveolar anesthetic concentration (MAC) and ventilation in halothane-anesthetized rats. Ketorolac in clinical (0.2 and 2 mg/kg) and large (20 and 40 mg/kg) IV doses did not affect the MAC of halothane (0.82% ± 0.02%). Resting end-tidal CO2 tension (5.1% ± 0.1%) and the slope of the CO2 response curves (70 ± 6 mL·min·%) were also unaffected by IV ketorolac. The mean arterial blood pressure did not significantly change after ketorolac in doses of 0.2, 2, or 20 mg/kg but decreased significantly (P < 0.05) after 40 mg/kg (placebo 99 ± 8 mm Hg; ketorolac 87 ± 6 mm Hg). This study demonstrates that MAC, ventilation, and mean arterial blood pressure are unaffected by clinical doses of IV ketorolac. Furthermore, the lack of effect on MAC and ventilation from larger doses suggests that ketorolac does not have mechanisms of action in the central nervous system.