Risk Factors for Poor Pain Control after Opioid Switching from Oxycodone Tablet to Fentanyl Patch.

Pain control becomes poor in some cases after opioid switching from oxycodone tablet (OXC) to fentanyl patch (FP). However, fewer studies on risk factors have been reported. In this study, we surveyed the states of pain control (PC) and opioid administration, patient background, laboratory test values, and concomitant drugs retrospectively in 86 patients switching from OXC to FP between June 2010 and April 2018 in Mazda Hospital and Hiroshima Prefectural Hospital. The subjects were divided into 2 groups based on the median number of days to the initial dose increase after switching to FP. Between the early (<7.5 d) and late (≥7.5 d) increase groups, a significant difference was noted in the presence or absence of liver metastasis (LM), concomitant drugs with a high protein binding rate (CDHPBR), and the state of PC before and after switching to FP (p < 0.05). Binary logistic regression analysis showed the presence of CDHPBR, absence of LM, and poor PC after switching were risk factors for early dose increase (presence of CDHPBR: odds ratios (OR), 3.30, 95% confidence interval (CI), 1.09-9.98; presence of LM: OR, 0.31, 95% CI, 0.10-0.93; good PC: OR, 0.23, 95% CI, 0.07-0.79, respectively). The initial dose increase after switching to FP was earlier in patients with CDHPBR and/or without LM than those without CDHPBR and with LM (p < 0.05, log-rank test). It was suggested that the analgesic effect of FP after switching from OXC is likely to be insufficient in patients treated with CDHPBR and patients without LM.

Factors Influencing the Appearance of Oxaliplatin-Induced Allergy.

Several studies reported that the administration of oxaliplatin often induced allergy, but few studies have analyzed the pathogenesis. In this study, we examined the relationship between the incidence of allergy and status of oxaliplatin administration, patient background, laboratory data, or combined drugs. The subjects were 144 patients with colorectal or gastric cancer in whom oxaliplatin administration was started and completed between 2010 and 2016. They were divided into 2 groups: allergy and non-allergy groups. We extracted important factors influencing its appearance using multivariate analysis, and analyzed items of which the influence was suggested, using receiver operating characteristic (ROC) analysis. In 11 patients (7.6%), allergy appeared. The median frequency of appearance was 9 times (range: 5-13), being similar to that previously reported. On multivariate analysis, albumin (Alb) was extracted as an important factor. The cut-off value of Alb for the risk of allergy was 4.1 g/dL. An increase in the number of protein conjugates may have increased the risk of functioning as a hapten. Furthermore, the results suggested that the more frequency of oxaliplatin administration might increase the incidence of allergy, although it was not extracted as an important factor. In addition to young and female patients, as previously indicated, careful follow-up may be necessary for those with an Alb level of ≥4.1 g/dL especially after the 6th course.