Pharmacokinetics, analgesic effect, and tolerability of a single preprocedural dose of intranasal fentanyl in patients undergoing drain removal after breast reduction or augmentation surgery: A prospective, randomized, double-blind, placebo-controlled study

Abstract

Background: Although acetaminophen is used to reduce pain after breast reduction or augmentation surgery, pain during the removal of the surgical drains is typically not specifically treated. Intranasally administered fentanyl may be suitable for pain control during removal of drains. The reported therapeutic window of fentanyl is between 0.2 and 1.2 ng/mL. Objective: The aim of this study was to evaluate the analgesic effect, tolerability, and pharmacokinetics of a single preprocedural dose of intranasal fentanyl administered before removal of surgical drains in patients who had undergone breast reduction or augmentation surgery. Methods: This was a randomized, double-blind, prospective study in healthy women (American Society of Anesthesiologists physical status I or II) between the ages of 18 and 65 years who were scheduled to undergo removal of surgical drains 1 to 4 days after breast reduction or augmentation surgery. A single dose of fentanyl nasal spray 0.05 mg/0.1 mL or placebo (preserved normal saline) 0.1 mL was administered 10 minutes before removal of drains. Because drain removal is generally carried out without specific analgesia, no rescue medication was provided. Pain intensity was measured on a visual analog scale (VAS) from 0 = no pain at all to 100 = worst pain possible. Pain intensity was evaluated immediately before administration of study medication (t = 0), at the time of drain removal (t = 10), and at 15, 20, 25, 40, and 70 minutes after administration of study medication. Safety measures included oxygen saturation, respiratory rate, heart rate, and blood pressure. Local and systemic adverse events were elicited by direct questioning throughout the study. Blood samples for pharmacokinetic analysis were collected at baseline and at 5, 10, 15, 30, 60, and 120 minutes after administration of study medication. The population pharmacokinetic parameters of fentanyl were calculated according to a 1-compartment open model with an iterative 2-stage Bayesian fitting procedure. Results: Thirty-six women were randomized to treatment, and 33 completed the study. Their mean (SD) age was 39.2 (13.0) years, and their mean weight was 68.9 (10.7) kg. Mean VAS scores at baseline were 14.8 (17.8) for the fentanyl group and 6.0 (9.7) for the placebo group ( P = NS); at the time of drain removal, the corresponding VAS scores were 31.0 (20.6) and 33.8 (25.7) ( P = NS). Analysis of a random-effects model with mean VAS scores as a function of time as the dependent variable indicated a significant difference in mean VAS scores between the fentanyl and placebo groups ( P = 0.006). The overall incidence of adverse events was 39.4% (13/33). Among the 17 patients in the fentanyl group, 8 reported ≥1 adverse event; among the 16 patients in the placebo group, 9 reported ≥1 adverse event. A mean estimated C max of 0.184 (0.069) ng/mL was reached at 13.76 (3.56) minutes after administration of intranasal fentanyl. The mean measured C max was 0.22 (0.088) ng/mL. Conclusions: In these women who had undergone breast reduction or augmentation surgery, a single preprocedural dose of intranasal fentanyl was significantly more effective than placebo in reducing pain intensity over the hour after removal of surgical drains. However, there was no significant difference in pain intensity between fentanyl at the time of drain removal and placebo. Intranasal fentanyl was generally well tolerated. At the dose used (0.05 mg), plasma fentanyl concentrations were below the reported therapeutic window.