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 mu g/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.