Pharmacokinetic study between a bilayer matrix fentalyl patch and a monolayer matrix fentanyl patch: single dose administration in healthy volunteers.

AIMS: Transdermal fentanyl is a well established treatment for cancer pain. The aim of the present study is to assess the relative bioavailability of fentanyl from two different transdermal systems by evaluating plasma drug concentrations after single administration of Fentalgon® (test), a novel bilayer matrix type patch, and Durogesic SMAT (reference), a monolayer matrix type patch. In the Fentalgon patch the upper 6% fentanyl reservoir layer maintains a stable concentration gradient between the lower 4% donor layer and the skin. The system provides a constant drug delivery over 72 h. METHODS: This was an open label, single centre, randomized, single dose, two period crossover clinical trial, that included 36 healthy male volunteers. The patches were applied to non-irritated and non-irradiated skin on the intraclavicular pectoral area. Blood samples were collected at different time points (from baseline to 120 h post-removal of the devices) and fentanyl concentrations were determined using a validated LC/MS/MS method. Bioequivalence was to be claimed if the 90% confidence interval of AUC(0,t) and C(max) ratios (test: reference) were within the acceptance range of 80-125% and 75-133%, respectively. RESULTS: The 90% confidence intervals of the AUC(0,t) ratio (116.3% [109.6, 123.4%]) and C(max) ratio (114.4% [105.8, 123.8%] were well included in the acceptance range and the C(max) ratio also met the narrower bounds of 80-125%. There was no relevant difference in overall safety profiles of the two preparations investigated, which were adequately tolerated, as expected for opioid-naïve subjects. CONCLUSIONS: The new bilayer matrix type patch, Fentalgon®, is bioequivalent to the monolayer matrix type Durogesic SMAT fentanyl patch with respect to the rate and extent of exposure of fentanyl (Eudra/CT no. 2005-000046-36).

Effect of Opioid Exposure on Efficacy and Tolerability of Sublingual Fentanyl and Subcutaneous Morphine for Severe Cancer Pain Episodes. Secondary Analysis From a Double-Blind Double-Dummy, Randomized Trial.

CONTEXT: Few studies have addressed the impact of previous opioid exposure on the effect of opioids for the treatment of severe cancer pain episodes. OBJECTIVES: We aimed to test whether previous exposure to higher opioid doses was associated with a reduced analgesic effect of fentanyl sublingual tablets (FST) and subcutaneous morphine (SCM) and whether it had an influence on their relative effect. METHODS: This is a secondary analysis of a placebo-controlled randomized trial comparing 100 µg FST with 5 mg SCM for the acute treatment of severe cancer pain episodes. The effect of previous opioid exposure (oral morphine equivalent daily dose from 20 to 120 mg) on pain intensity difference (PID) and side effects at 30 and 60 minutes after administration (PID 0-30 minutes, PID 0-60 minutes, and adverse events 30-60 minutes) and on re-medication for inefficacy, was studied by multivariable linear and logistic regression models and statistical tests for interaction. RESULTS: A total of 114 patients were enrolled. Results indicate modest and nonstatistically significant effect of previous opioid exposure on all the outcomes examined (P = 0.11, P = 0.35, P = 0.07, and P = 0.52, respectively, for PID 0-30 minutes, re-medication, PID 0-60 minutes, and adverse events 30-60 minutes). Nonstatistically significant tests for interaction for all models indicated a lack of impact of previous opioid exposure on the difference in the analgesic effect between treatments. CONCLUSION: In this study, we could not demonstrate an effect of previous opioid exposure, from 20 to 120 mg oral morphine equivalent daily dose, on the absolute and relative efficacy and tolerability of 100 µg FST and 5 mg SCM for severe cancer pain episodes.

Fentanyl Sublingual Tablets Versus Subcutaneous Morphine for the Management of Severe Cancer Pain Episodes in Patients Receiving Opioid Treatment: A Double-Blind, Randomized, Noninferiority Trial.

Purpose Fentanyl sublingual tablets (FST) are a potentially useful alternative to parenteral opioids such as subcutaneous morphine (SCM) to treat severe cancer pain episodes. No direct comparison between FST and SCM is available. The aim of this study was to test noninferiority of FST versus SCM during the first 30 min postadministration. Methods Patients receiving stable opioid therapy and experiencing a severe pain episode were randomly assigned to either 100 µg FST or 5 mg SCM in a double-blind, double-dummy trial. Average pain intensity (PI) assessed on a 0 to 10 numerical rating scale at 10, 20, and 30 min postadministration was the main end point. Analysis of covariance, adjusted by baseline PI, was the main analysis. The noninferiority margin (NIm) for the between-group difference was set at -0.6, that is, equal to one third of the minimum clinically important PI difference of two points. Results A total of 114 patients were randomly assigned to either FST (n = 58) or SCM (n = 56). One patient (in the FST group) withdrew consent before drug administration and was excluded from analysis. Baseline mean PIs were 7.5 in both groups; mean average PIs assessed at 10, 20, and 30 min postadministration were 5.0 and 4.5 for FST and SCM, respectively, with the 95% CI of the between-group difference including the NIm (-0.49; 95% CI, -1.10 to 0.09). Patients taking FST received a second drug dose after 30 min more frequently than did patients taking SCM (51% v 37%, respectively; risk difference, -13%; 95% CI, -30% to 3%). Both treatments were well tolerated, with average follow-up adverse event scores below the response of "A Little." Ninety-three percent of patients preferred the sublingual administration. Conclusion This trial did not show noninferiority of FST versus SCM within the chosen NIm. Both treatments were safe, and patients preferred the sublingual route of administration. FST provides analgesia with modest to moderate increased risk of lower efficacy compared with SCM.