Pharmacokinetic Analysis, Analgesic Effects, and Adverse Effects of Tapentadol in Cancer Patients with Pain.

In this study, we conducted a pharmacokinetic analysis of tapentadol (TP) in Japanese patients with cancer pain and identified covariates influencing pharmacokinetic parameters. In addition, the analgesic effects and adverse effects of TP were investigated. Data were collected from in-patients with cancer pain who had been administered TP as an extended-release formula. The median (range) estimated clearance (CL/F) and distribution volume (Vd/F) of TP were 86.7 (31.3-213.7) L/h and 1288 (189-6736) L, respectively. There was a strong negative correlation between CL/F and age, Child-Pugh score, and albumin-bilirubin (ALBI) score. The subjects were further divided into two groups according to the factors highly correlated with CL/F. The CL/F of patients in the Child-Pugh B group was 0.46-times that of patients in the Child-Pugh A group. In addition, the CL/F of patients with an ALBI score > -2.40 was 0.56-times that of patients with ALBI scores ≤-2.40, and both differences were statistically significant (p < 0.05). The mean intensity of pain over 24 h was investigated daily from before starting TP for the first 7 d of the treatment. TP reduced pain in six of nine patients; the mean pain visual analogue scale score decreased significantly from 59.2 mm before administration to 42.5 mm at days 5-7. Overall, the Child-Pugh and ALBI scores significantly affected the clearance of TP, which was reduced in patients with impaired liver function. These results suggest that TP is an opioid with a sufficient analgesic effect for cancer patients.

[Clinical Effects of Opioid Switching to Tapentadol - Retrospective Analysis of Efficacy and Adverse Effects].

The objective of our study was to evaluate the efficacy and adverse effects of opioid switching to tapentadol(TP). It was a retrospective survey carried out at the Kitasato University Hospital outpatient clinic between September 2014 and May 2016. We evaluated pain intensity using the visual analogue scale and the occurrence of adverse effects before switching, at the first evaluation after switching, and during the steady state of TP administration. We included 10 patients; of these, 3 patients discontinued TP owing to uncontrolled pain. The conversion ratio of the previously administered opioids to TP was 1.17 at the time of the first evaluation after switching and 1.42 during the steady state. The mean(±SD)pain intensity was 4.2±2.2 before opioid switching and 4.6±2.2 at the time of the first evaluation after switching. The mean(±SD)pain intensity in the 7 patients excluding the 3 patients who discontinued TP was 4.3±2.0 before opioid switching and 2.7±1.9 during the steady state. Somnolence improved in 5 patients and constipation improved in 2 patients when a stable dose was achieved. Opioid switching to TP was appropriately accomplished using the conversion ratio. Furthermore, pain, sleepiness, and constipation improved following successful titration. These data suggest that TP can be useful in the treatment of cancer pain, in addition to the currently used opioid preparations.