The fentanyl transdermal system (Duragesic) is an opioid analgesic indicated for the management of chronic moderate to severe pain. The purpose of this analysis is to estimate its economic value compared to two long-acting oral opioids. A cost-utility analysis was performed using a three-phased decision analytic model. The transdermal system had the highest expected cost during the first year of therapy ($2,491), moderately higher than the cost of a year of therapy with controlled-release morphine ($2,037) or controlled-release oxycodone ($2,307). The system also had the highest expected number of quality-adjusted life-days (QALDs) (244 compared to 236 for morphine and 231 for oxycodone), despite conservative assumptions. The fentanyl transdermal system achieved incremental cost-utility ratios of $20,709 (vs. morphine) and $5,273 (vs. oxycodone) per quality-adjusted life year (QALY) gained. In a conservative modeled analysis, the fentanyl transdermal system led to increased QALDs at a nominal increased cost. In the absence of head-to-head clinical trials, models help clarify cost and outcome trade-offs and provide a consistent theoretical framework for use by individual decisionmakers. (C) U.S. Cancer Pain Relief Committee, 2001.