Clinical Usefulness of Long-term Application of Fentanyl Matrix in Chronic Non-Cancer Pain: Improvement of Pain and Physical and Emotional Functions

BACKGROUND: Opioids are recently recommended for those who do not gain adequate pain relief from the use of acetaminophen or nonsteroidal anti-inflammatory drugs. Medical opioids are administered in various routes, and transdermal opioid products that can make up for the weaknesses of the oral or intravenous products have been developed. This study is to evaluate the clinical usefulness of fentanyl matrix in terms of the long-term improvement in pain and physical and mental functions. METHODS: This was a multicenter, open, prospective, observational study that was conducted in 54 institutions in Korea. Patients with non-cancerous chronic pain completed questionnaires, and investigators also completed questionnaires. A total of 1,355 subjects participated in this study, and 639 subjects completed the study. Subjects received transdermal fentanyl matrix (12 µg/hr, 25 µg/hr, or 50 µg/hr depending on the patient's response and demand). Subjects visited at 29 ± 7 days, 85 ± 14 days, and 169 ± 14 days after administration, respectively, to receive drug titration and fill out the questionnaires. The results were analyzed using the intention-to-treat (ITT) analysis, full analysis set (FAS), and per-protocol (PP) analysis. The FAS analysis included only 451 participants; the PP analysis, 160 participants; and the ITT analysis, 1,355 participants. RESULTS: The intensity of pain measured by the Numeric Rating Scale decreased from 7.07 ± 1.78 to 4.93 ± 2.42. The physical assessment score and mental assessment score of the Short-Form Health Survey 12 improved from 28.94 ± 7.23 to 35.90 ± 10.25 and from 35.80 ± 11.76 to 42.52 ± 10.58, respectively. These differences were significant, and all the other indicators also showed improvement. Adverse events with an incidence of ≥ 1% were nausea, dizziness, vomiting, and pruritus. CONCLUSIONS: The long-term administration of fentanyl matrix in patients with non-cancerous pain can reduce the intensity of pain and significantly improves activities of daily living and physical and mental capabilities.

Influence of body fat in cancer patients on residual content of used fentanyl matrix patches

<b>Purpose</b>: The objective of this study was to investigate whether body fat rate (BFR) and triceps skinfold thickness (TSF) are associated with estimated fentanyl absorption in patients treated with the fentanyl transdermal matrix patch for moderate to severe cancer pain, by measuring the residual content of fentanyl in used matrix patches. <b>Methods</b>: Adult Japanese inpatients experiencing chronic cancer-related pain and receiving treatment for the first time with a transdermal fentanyl matrix patch (Durotep®MT patch) were included in the present study. During the initial application period, BFR was measured using a body fat scale, and TSF was measured by an experienced nurse with an adipometer. One patch was collected from each patient. The residual fentanyl content in used matrix patch was determined by high-performance liquid chromatography. The transdermal fentanyl delivery efficiency was estimated based on the fentanyl content of the used matrix patches. <b>Results</b>: Fifteen adult patients (5 males and 10 females) were included in this study. Nine patches with a release rate of 12.5μg/h and 6 patches with a release rate of 25μg/h were collected. The application site was the chest or upper arm. BFR and TSF both showed a significant positive correlation with delivery efficiency. <b>Conclusion</b>: In malnourished or low-body fat patients receiving DMP, pain intensity should be more carefully monitored, and fentanyl dose adjustment may be required. Additional parameters, such as nutritional status including body fat change, the degree of dry skin, and plasma fentanyl concentration, also require detailed evaluation. Palliat Care Res 2010; 5(2): 206-212