[Etomidate using a new solubilizer. Experimental clinical studies on venous tolerance and bioavailability]

Area of Science:

• Anesthesiology
• Pharmacology
• Clinical Medicine

Background:

• Intravenous etomidate commonly causes pain on injection and thrombophlebitis.
• Previous investigations suggested lipid emulsions as a potential solvent to mitigate these side effects.
• The efficacy of etomidate in lipid emulsion for general anesthesia required further clinical validation.

Purpose of the Study:

• To evaluate the safety and efficacy of etomidate formulated in a lipid emulsion compared to propylene glycol.
• To assess the impact of the solvent on etomidate's pharmacokinetic and pharmacodynamic properties.
• To determine the incidence of injection pain and postoperative venous complications.

Main Methods:

• Pharmacodynamic (EEG) and pharmacokinetic (HPLC) studies were conducted on 16 volunteers.
• A randomized clinical trial involved 100 patients receiving either etomidate in propylene glycol or lipid emulsion.
• Doses of 0.3 mg/kg etomidate were administered intravenously over 60 seconds.

Main Results:

• Etomidate in lipid emulsion showed no local irritation or venous complications post-injection.
• Patients receiving etomidate in propylene glycol experienced injection pain (36%) and significant phlebitis/thrombophlebitis (22% by day 7).
• Anesthetic induction times, blood pressure, and heart rate were similar between groups, with lipid emulsion potentially retaining etomidate in particles.

Conclusions:

• Lipid emulsion as a solvent effectively abolishes pain on injection and postoperative thrombophlebitis associated with etomidate.
• The new etomidate formulation in lipid emulsion offers an improved safety profile without compromising anesthetic efficacy.
• This formulation represents a significant advancement in etomidate administration for general anesthesia.