fentanyl + isoflurane

Fentanyl + isoflurane refers to the concurrent use of two anesthetic agents—fentanyl, a potent synthetic opioid analgesic, and isoflurane, a volatile inhalational general anesthetic. This combination is commonly used in both human and veterinary anesthesia to provide balanced anesthesia with enhanced analgesia and reduced requirements for each agent. Fentanyl acts primarily as a μ-opioid receptor agonist, providing strong analgesia and reducing the minimum alveolar concentration (MAC) of isoflurane required for surgical anesthesia by up to 60–63% at clinically relevant plasma concentrations[1][5]. Isoflurane induces general anesthesia by enhancing inhibitory neurotransmission via GABA-A receptors and other central nervous system targets. The combination allows for lower doses of each drug, potentially minimizing side effects such as cardiovascular depression associated with higher doses of either agent alone[2][4]. However, their combined use can result in significant decreases in heart rate, mean arterial pressure, and cardiac index; careful monitoring during administration is essential[2].