Abstract ID: A4

Abstract Title: Effect of Patient Age and Body Mass Index (BMI) on the Efficacy of the Iontophoretic Fentanyl HCl Patient-Controlled Transdermal System (PCTS) vs IV PCA Morphine in the Management of Acute Postoperative Pain

Authors: Rathmell J¹, Hewitt D², Wu S³
Fletcher Allen Health Care, University of Vermont Burlington VT ¹, Johnson & Johnson Raritan NJ ², Johnson & Johnson Raritan NJ ³
Poster Type: Poster

ABSTRACT BODY

Introduction: A novel, needle-free, iontophoretic, fentanyl HCl patient-controlled transdermal system (fentanyl HCl PCTS) has been demonstrated to be therapeutically equivalent in efficacy to IV PCA morphine for the management of moderate-to-severe acute postoperative pain. To determine the specific patient populations for whom an analgesic modality is appropriate, an examination of the effects of demographic factors on analgesic efficacy must be performed. The demographic factors of patient age and body mass index (BMI) are known to affect drug metabolism and analgesic absorption and distribution, respectively, both of which may influence analgesic efficacy. This analysis examines the effects of patient age and BMI on the efficacy of the fentanyl HCl PCTS vs morphine IV PCA.

Methods: Adult patients (N=636) undergoing major surgery were enrolled. After surgery, patients were titrated to comfort with opioids and randomized 1:1 to receive the fentanyl HCl PCTS or IV PCA morphine. The fentanyl HCl PCTS delivered 40 µg fentanyl over the course of 10 minutes, up to 6 doses/hour, upon patient activation of the system. IV PCA delivered morphine in 1-mg boluses, up to 10 mg/hour, when the patient pressed the dosing button. Ratings for the primary efficacy endpoint, patient global assessment (PGA) of the pain control method (“poor,” “fair,” “good,” or “excellent”), were used to evaluate analgesic efficacy; assessments were performed at 24 hours following the initiation of treatment. The proportions of patients reporting successful ratings (“excellent” or “good”) on the PGA within each age group (<65, 65–74, ≥75 years) and BMI group (<25, 25–29, and ≥30) were compared between treatment groups using the Chi-square test.

Results: No trends in efficacy were observed with increasing age or BMI for the fentanyl HCl PCTS or morphine IV PCA groups. The proportions of successful PGA ratings were similar between the fentanyl HCl PCTS and morphine IV PCA groups across age groups (Figure 1): <65 (n = 237 and n = 255, respectively; P = 0.232); 65–74 (n = 50 and n = 40, respectively; P = 0.387); and ≥75 (n = 23 and n = 21, respectively; P = 0.622). Likewise, the proportions of successful PGA ratings were similar between the fentanyl HCl PCTS and morphine IV PCA groups across BMI groups (Figure 2): <25 (n = 96 and n = 90, respectively; P = 0.92); 25–29 (n = 94 and n = 108, respectively; P = 0.93); and ≥30 (n = 120 and n = 118, respectively; P = 0.14).

Conclusions: Results of this analysis suggest that the fentanyl HCl PCTS and IV PCA morphine provide similar rates of successful pain control in adults following major surgery, regardless of patient age or BMI.

ATTACHED FILES

A4_Figure 1.doc

A4_Figure 2.doc

Reg Anesth Pain Med 2005; 30(3):A4