Characteristics and reasons for low-dose fentanyl patch use in opioid-naïve versus non-naïve patients with cancer pain

BACKGROUND: Transdermal fentanyl is usually reserved for opioid-tolerant patients, but in Japan, a low-dose transdermal fentanyl patch (0.5 mg, delivering ~6 μg/h; Fentos tape®) has been approved for opioid-naïve cancer pain. However, real-world data on how this formulation is prescribed are limited. This study aimed to compare patient characteristics and prescribing reasons between opioid-naïve and non-naïve patients and to identify factors associated with opioid-naïve initiation. METHODS: We retrospectively reviewed 107 patients who were started on a low-dose transdermal fentanyl patch (0.5 mg, delivering ~6 μg/h) at a Japanese university hospital. Patients were classified as opioid-naïve [no prior opioid (n = 36)] or non-naïve [switched (n = 71)]. Data on demographics, cancer type, department, care setting, and reasons for patch use were categorized. Multivariate logistic regression examined factors associated with opioid-naïve initiation. RESULTS: Opioid-naïve patients more often had gastrointestinal cancer and were managed by gastrointestinal (GI)-related departments. Age and inpatient status were similar between the groups. The distribution of reasons for prescribing did not significantly differ (oral intake difficulty, 39% vs. 42%; bowel problems, 14% vs. 10%; renal dysfunction, 8% vs. 4%). GI cancer (adjusted odds ratio [OR], 4.43; 95% confidence interval [CI], 1.75-11.18) and GI-related department (adjusted OR, 4.57; 95% CI, 1.67-12.53) were independently associated with opioid-naïve initiation. CONCLUSION: In this cohort, low-dose transdermal fentanyl patches were preferentially used as first-line strong opioids in patients with GI cancers and those under GI specialist care, rather than being limited to those with clear swallowing difficulty.