To determine the safety and efficacy of transdermal fentanyl for pain relief in cancer patients and to compare the effects on patients according to whether they had previously received strong opioids, weak opioids or non-opioid analgesia.
Cancer patients requiring strong analgesia were recruited into an open-label, multicentre study, conducted in eight countries. Patients received transdermal fentanyl treatment for 28 days. Pain severity, overall satisfaction with pain control, convenience of use of patches and treatment preferences were recorded daily.
Of the 292 participants, 135 had previously received a strong opioid, 84 had previously received a weak opioid and 73 had received no regular opioids. Thirty-eight patients did not complete the study, mainly due to adverse events. For all groups the proportion of patients with 'good to excellent' pain control increased after transdermal fentanyl treatment. Transdermal fentanyl was well tolerated, with the most common treatment-related adverse events being nausea, vomiting and constipation. The percentage of strong-opioid-tolerant patients with constipation decreased following transdermal fentanyl treatment and increased slightly in the strong-opioid-naïve groups. Most patients rated the convenience of the patches as 'good to excellent', and most preferred transdermal fentanyl to their previous therapy.
Transdermal fentanyl is an effective and well-tolerated treatment for cancer-related pain for patients regardless of whether they have previously received opioids. Previous guidelines have often advocated initial dose finding with short-acting opioids but this study demonstrates that such a complex titration and conversion schedule may not be necessary,and that treatment may be initiated directly with long-acting formulations such as transdermal fentanyl when previous analgesic therapy fails to provide adequate relief.