This research is a subanalysis of a broader, head-to-head study published earlier this year in the Journal of the American Medical Association (JAMA). The complete set of data showed that 316 adult patients receiving IONSYSTM following major surgery experienced similar pain relief as that experienced with IV PCA morphine. This subanalysis focuses on the women in the study who had undergone gynecologic surgery. Patients received either IONSYSTM fentanyl HCl 40mcg -- a system that is designed to be the first and only needle-free, patient-controlled, transdermal analgesic to treat acute pain -- or the current standard of therapy, morphine via IV PCA. IONSYSTM currently is under development and not yet commercially available.
Researchers reported no statistically-significant differences between the two methods in patients' overall pain control, the amount of supplemental pain medication required, or the number of patients withdrawing from the study due to inadequate pain relief. Side effects were similar in both groups.
"In 2002, there were more than a million gynecologic surgeries performed in the United States," said Shireen Ahmad, M.D., Assistant Professor, Department of Anesthesiology at Northwestern University. "In this subanalysis, IONSYSTM provided post-operative pain relief to most patients undergoing gynecologic surgery without the needles, lines and pumps needed for IV PCA."
Patients in the study were randomized to receive either IONSYSTM - which delivers 40 micrograms of fentanyl on demand, up to six doses per hour - or one milligram of morphine on demand, up to 10 doses per hour, via IV PCA.
Among 275 women undergoing gynecologic surgery, 85% of IONSYSTM patients, or 117 of 138, and 84% of IV PCA patients, or 115 of 137, rated their pain control as excellent or good during the first 24 hours of treatment (p=0.848). Patient measurements of pain intensity were similar between IONSYSTM and the IV PCA groups at four and at eight hours, and also at the last pain intensity score. A similar proportion of patients in each group requested supplemental pain medication during the first three hours of treatment, 18.1% of IONSYSTM patients and 21.2 % of IV PCA patients.
Inadequate pain relief resulted in the withdrawal of 8.7% or 12 patients in the IONSYSTM group and 4.4% or 6 patients in the IV PCA group. The incidence of adverse events was similar in IONSYSTM and IV PCA groups, respectively. Nausea 50% vs. 57%, headache 19% vs. 10%, itching 11% vs. 15%, and vomiting 9% vs. 6%, were the most common.
IV PCA systems, which are currently used to administer medications for acute pain in the hospital setting, consist of a programmable machine, a pole and connective tubing, which are attached to the patient via an intravenous line into their arm. By contrast, IONSYSTM is a lightweight, compact system, approximately the size of a credit card that adheres to a patient's upper arm or chest. When a dose of pain medication is needed, the patient pushes a button located on the system. This activates a very low-intensity electrical current - not felt by the patient - that delivers a pre-programmed dose of fentanyl through the skin. The medication is absorbed into the body over a 10-minute period.
IONSYSTM is intended for use only in medical institutions, such as hospitals and surgical centers, by patients under medical supervision and direction.
IONSYSTM contains fentanyl, an opioid agonist and a Schedule II controlled substance with high potential for abuse similar to hydromorphone, methadone, morphine and oxycodone. Fentanyl can be abused in a manner similar to other opioid agonists, legal or illicit. This should be considered in situations where the healthcare professional is concerned about an increased risk of misuse, abuse or diversion. Fentanyl can cause life threatening respiratory depression. Inappropriate use of IONSYSTM, or unintended exposure to the fentanyl gel within the system, could lead to the absorption of a potentially fatal dose of fentanyl. Therefore, the fentanyl gels should not be permitted to touch the fingers or mouth. Oral contact or ingestion of the fentanyl-containing gel may cause life-threatening hypoventilation or death.
The ALZA Corporation, headquartered in Mountain View, California, developed the E-TRANS® transdermal technology used in IONSYSTM. ALZA is working to complete the steps necessary for final marketing approval in the United States, following receipt of the approvable letter from FDA. Once approved, Ortho-McNeil Pharmaceutical, Inc. will market the system in the United States. Janssen-Cilag will market IONSYSTM in Europe; a marketing authorization application was submitted to the European Medicines Agency in June 2004. Ortho-McNeil, ALZA and Janssen-Cilag are Johnson & Johnson companies.