Factors predicting requirement of high-dose transdermal fentanyl in opioid switching from oral morphine or oxycodone in patients with cancer pain.

OBJECTIVES: To identify predictive factors requiring high-dose transdermal fentanyl in opioid switching from oral morphine or oxycodone to transdermal fentanyl in patients with cancer pain.

METHODS: The participants were 76 hospitalized terminal cancer patients who underwent opioid switching from oxycodone or morphine sustained-release tablet to transdermal fentanyl at our hospital between January 2009 and June 2010. The conversion dose was calculated as transdermal fentanyl (25 μg/h)/oral morphine (60 mg) or oxycodone (40 mg)=1. The response evaluated was the dose conversion ratio [transdermal fentanyl/oral morphine or oxycodone (conversion dose to fentanyl)]=Y and was taken to be 0 for Y≤1, 1 for 1<Y≤2, 2 for 2<Y≤3, and 3 for 3<Y. Predictors evaluated were factors potentially impacting pain. Ordered logistic regression analysis was carried out to identify the predictive factors requiring high-dose transdermal fentanyl in opioid switching.

RESULTS: Breast cancer [odds ratio (OR)=8.218; 95% confidence interval (CI), 1.219-55.407; P=0.0305], total protein level (OR=0.630; 95% CI, 0.408-0.974; P=0.0377), alanine aminotransferase level (OR=1.017; 95% CI, 1.001-1.033; P=0.0390), advanced age (OR=3.700; 95% CI, 1.360-10.063; P=0.0104), and male sex (OR=3.702; 95% CI, 1.355-10.115; P=0.0107) were found to be significant predictive factors requiring high-dose transdermal fentanyl in opioid switching.

DISCUSSION: Our study indicates that breast cancer, total protein, alanine aminotransferase, advanced age, and male sex are significant predictors of a need for higher dose transdermal fentanyl in opioid switching. Our results are considered likely to contribute to the establishment of evidence-based medicine in pain relief and palliative care.