Plasma fentanyl concentrations in awake cats and cats undergoing anesthesia and ovariohysterectomy using transdermal administration.

Objective: To measure the plasma fentanyl concentrations achieved over time with transdermal fentanyl patches in awake cats and cats undergoing anesthesia and ovariohysterectomy.

Study Design: Randomized prospective experimental study.

Animals: Twenty-four purpose-bred cats.