Transdermal fentanyl patches versus patient-controlled intravenous morphine analgesia for postoperative pain management

Background: Acute and severe pain is common in patients postoperatively and should be correctly managed. In the past years studies on preparing better postoperative pain control have resulted in development of postoperative pain management guidelines. Perhaps, one of the major improvements in managing postoperative pain is the development of the patient-controlled analgesia systems (PCA), especially through intra venous (IV), extradural and transdermal routes, which has resulted in marked improvements in acute postoperative pain management. Physicians administrate potent opioids for moderate to severe post-surgical pains. Morphine is the most commonly IV-PCA administrated analgesic. The fentanyl iontophoretic transdermal system (fentanyl ITS) is also another efficient option for pain management.

Objectives: The aim of this study was to compare the analgesic effects of these two routine postoperative pain control systems.

Patients and methods: We enrolled 281 patients (224 males, 57 females) in this blind randomized controlled clinical trial, who had undergone an orthopedic surgery, with the mean age of 33.91 ± 14.45 years. Patients were randomly divided into two groups; in group A patients received IV-morphine PCA pump and in group B fentanyl transdermal patches were attached on patients' arms. The severity of the pain was registered according to Visual Analogue Scale in specially designed forms by pain-trained nurses in two steps; first after the surgery and next before the beginning of analgesic effects. After 24 hours, the pain score was assessed again.

Results: No significant difference was observed in mean pain intensity score at the first patient assessment. Mean pain intensity scores were also similar in both groups at the last measured time point (P > 0.05). Differential pain intensity scores, showing the impacts of analgesic system on the pain experience of the patients was also similar between fentanyl patches (6.48 ± 2.20) and morphine PCIA (6.40 ± 1.80). (P > 0.05) Mean patient satisfactory score (scale: 0-100) was also similar in both groups (P > 0.05). The percentage of patients, whose differential pain intensity scores at 24 hours reached our pain management goal was similar between fentanyl and morphine groups (P > 0.05). The percentage of patients with at least one adverse event was significantly higher in fentanyl group (P < 0.05). The most frequent adverse events were nausea, vomiting and itching. In none of the groups, no patient experienced serious adverse events related to the studied medications.

Conclusions: Although both pain killing therapeutic regimens are safe and effective for postoperative pain management, regarding the easy usage of the patches, lower risk of abuse and cost-effectiveness in the Iranian market, it is recommended for use in Iranian hospitals and trauma centers and in countries with similar socioeconomic situations.