Postoperative Pain Management With a Patient-Controlled Transdermal Delivery System for Fentanyl

Peter J. S. Koo

Disclosures

Am J Health Syst Pharm. 2005;62(11):1171-1176. 

In This Article

Abstract and Introduction

Purpose: The efficacy and safety of fentanyl hydrochloride patient-controlled trans-dermal system (PCTS) for management of acute postoperative pain are discussed.
Summary: Fentanyl hydrochloride PCTS is a self-contained, needle-free, credit-card-sized fentanyl-delivery system that is worn on the patient's arm or chest. The system uses iontophoretic technology to actively deliver preprogrammed doses of fentanyl into the systemic circulation when activated by the patient on demand. PCTS is as safe and effective as i.v. morphine patient-controlled analgesia and superior to placebo for managing acute postoperative pain. Fentanyl absorption from PCTS is clinically insignificant when the device is not activated. This contrasts with the transdermal fentanyl patch, which delivers fentanyl continuously for 72 hours via passive absorption and is indicated only for use in the management of chronic pain.
Conclusion: Fentanyl hydrochloride PCTS is a self-contained iontophoretic fentanyl-delivery system that provides patients control over pain management and consistent management of pain without analgesic peaks and troughs.

Opioids are widely used for managing moderate to severe acute pain in the postoperative setting.[1] Typical routes of postoperative opioid administration are intravenous (i.v.), intramuscular (i.m.), and epidural.[2] After pain medication is administered systemically, an analgesic effect does not occur until a threshold serum concentration is reached[3]; serum concentrations only slightly higher than the threshold concentration (the minimum effective analgesic concentration [MEAC]) are required to produce effective pain control. Increasing serum concentrations beyond the MEAC does not improve analgesic effectiveness but does increase the risk of adverse events, such as oversedation and respiratory depression.

One common method of postoperative opioid delivery is patient-controlled analgesia (PCA), which is usually administered via the i.v. or epidural route.[4] PCA enables patients to actively participate in their pain management, and, because this modality allows for the frequent delivery of small doses, the analgesic peaks and troughs associated with the three- to four-hour dosage intervals commonly associated with i.v. and i.m. administration are eliminated.[5] The most frequently used opioids in PCA delivery systems are morphine and fentanyl.[6]

In contrast to PCA, conventional i.m. administration of analgesics is complex, and delays between injections may result in periods of increased acute pain. Because of the relatively large i.m. doses necessary to achieve an analgesic effect that lasts for the dosage interval, absorption may be variable and prolonged, increasing the possibility of sedation and respiratory depression.[7] With PCA, there are few delays in administration, and the doses are small enough that the MEAC may be reached while minimizing adverse events associated with higher serum opioid concentrations.

Research indicates that patients prefer PCA to bolus i.v. and i.m. analgesic administration techniques.[6,8,9,10,11,12,13,14,15,16] Reasons for this vary, but many patients prefer to actively participate in their pain management and feel they obtain better relief and worry less about overmedication with PCA.[6,17,18,19] I.V. PCA is widely used for controlling acute pain after major surgery,[4] and it is usually initiated after analgesia has been accomplished with loading doses of i.v. opioids.[15] The patient can then self-administer small opioid doses as needed by pressing a button on a handset connected to an infusion pump. A microprocessor within the unit controls the rate and amount of opioid delivered.

While on-demand administration makes i.v. PCA attractive to patients, it has several limitations. Complications, including i.v. line occlusion and infiltration at the catheter site, may compromise analgesic delivery.[20] I.V. PCA requires frequent evaluation by the hospital staff to ensure that pumps are functioning properly and that the correct doses are being administered.[21] In addition, programming errors may occur if the nursing staff is not adequately educated about system operation.[22] Mistakes have led to opioid overdoses and potentially serious sequelae, including respiratory depression, seizures, hypertension, hallucinations, somnolence, nausea, vomiting, decreased intestinal motility, urinary retention, and, in rare cases, death.[22,23,24,25] Furthermore, the pump apparatus and i.v. lines that are required for system function may hinder patient mobility, which may lead to postoperative complications.[26] Although some i.v. PCA systems use prefilled medication cartridges, others may require pharmacists to fill syringes with standard opioid solutions under sterile conditions. Finally, although the cost associated with i.v. PCA has not been fully characterized in a controlled trial setting, evidence suggests that it is more costly than conventional i.m. analgesic therapy.[21,27] In addition to the initial capital expenditure for PCA pumps, the ongoing cost of pump maintenance, replacement batteries, i.v. tubing, and drug cartridges must be factored into economic considerations.

Fentanyl hydrochloride patient-controlled transdermal system (PCTS) is a noninvasive active analgesic delivery system that is under development for use in the management of acute pain in a medically supervised setting. PCTS was recently granted approvable status by FDA, and the system (previously referred to as E-Trans) will be marketed under the brand name IONSYS by Ortho-McNeil Pharmaceutical in the United States. The system provides the benefits of PCA without the limitations. The features and uses of PCTS are different from those of Duragesic (Janssen Pharmaceutica Products, LP, Titusville, NJ), a trans-dermal patch that passively delivers fentanyl continuously.

The objective of this article is to describe the efficacy and safety of fentanyl hydrochloride PCTS for acute pain management, review its pharmacokinetics, and differentiate it from the passive transdermal fentanyl patch, which is indicated for chronic pain management.

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