13.7 : 肠外麻醉药：概述

Parenteral anesthetics rapidly induce general anesthesia when infused intravenously.

Most agents target GABA_A receptors for sedation and hypnotic effects. However, ketamine induces dissociative anesthesia and analgesia by inhibiting NMDA receptors.

Propofol is a commonly used parenteral anesthetic, while its prodrug,  fospropofol, is used for sedation during diagnostics.

These drugs have a short elimination half-life, making them suitable for anesthesia induction and maintenance.

However, they pose adverse effects, including hypotension due to vasodilation and potential myocardial contractility depression. Propofol can cause respiratory depression, necessitating oxygenation, and ventilation monitoring.

Its prolonged use may trigger PRIS, a rare, potentially fatal condition marked by metabolic acidosis and hyperlipidemia.

Adjunct agents include benzodiazepines for sedation and amnesia and dexmedetomidine, an α₂ adrenergic agonist, for short-term sedation.

Additionally, opioid analgesics are used to manage postoperative analgesia and intraoperatively as part of a balanced anesthesia regimen.