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.