Objective: This study aimed to investigate the effect of nutritional status on estimated fentanyl absorption in cancer patients being treated with a fentanyl transdermal patch (FP), by measuring the residual fentanyl content in used patches. Methods: 24 adult Japanese inpatients receiving FP treatment for chronic cancer-related pain were enrolled. During FP application, the nutritional risk of the patients was measured using the Malnutrition Universal Screening Tool (MUST) and Nutritional Risk Screening 2002 (NRS 2002), both of which are nutrition screening tools used widely in Japan. We then classified the patients into low-, medium-, and high-risk groups according to the nutritional risk measured by MUST, and compared the transdermal fentanyl delivery efficiency (FE) between that groups. Results: The FE, which is estimated by the residual fentanyl content in used FPs collected from the patients, was found to be decreased in the high-risk group. According to NRS 2002, the mean transdermal fentanyl delivery efficiency in the high-risk group was significantly lower than that in the low-risk group. Conclusion: These results showed that changes in nutritional status affect FE, and that poor nutritional status might decrease transdermal fentanyl absorption in cancer patients.

Purpose: 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. Methods: 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. Results: 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. Conclusion: 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