Plasma protein binding of etomidate in different age groups and in patients with chronic respiratory insufficiency.

Plasma protein binding of etomidate, an intravenous anesthetic agent of basic nature, has been studied in healthy subjects of different age groups and in patients with chronic respiratory insufficiency. No differences were detected in the plasma protein binding of etomidate between young children and young adults, but elderly subjects exhibited decreased binding. Low levels of serum albumin may account in part for this decreased binding, but differences in the amount of etomidate bound per mol of albumin and in affinity constants for the binding were also apparent between young adults and elderly individuals. Although plasma protein binding of etomidate may also be decreased in patients with chronic respiratory insufficiency, further studies are needed to clarify this point.