A safe and effective method for converting cancer patients from intravenous to transdermal fentanyl

Therapeutic fentanyl blood levels are reached approximately 12-16 hours after the initial application of transdermal fentanyl patches. For this reason, fentanyl patches should not be used to treat acute exacerbations of cancer pain. Acute cancer-related pain can be treated with fentanyl administered by continuous intravenous infusion (CII) in combination with patient-controlled analgesia (PCA). Patients then can be switched from intravenous (IV) to transdermal fentanyl once stable pain relief has been achieved. The objective of the current case series was to evaluate and describe the safety and effectiveness of a method for converting hospitalized patients with cancer-related pain from IV to transdermal fentanyl.

The authors prospectively evaluated 15 consecutive cancer patients during the conversion from IV to transdermal fentanyl. In all patients, a transdermal patch delivering fentanyl at a rate equivalent to that of the final continuous IV infusion was applied. The CII rate was decreased by 50% 6 hours after application of the fentanyl patch and then discontinued after another 6 hours. Demand boluses of IV fentanyl equivalent in dosage to 50-100% of the final CII rate remained available via PCA during the 24 hours after patch application. Pain intensity (on a scale of 0-10), sedation (on a scale of 0-3), and hourly PCA administration (microg/hr) were assessed and recorded immediately prior to application of the fentanyl patch and 6, 12, 18, and 24 hours thereafter.

Pain intensity, sedation, and hourly PCA administration appeared to remain stable throughout the transition from IV to transdermal fentanyl.

The results of the current study demonstrate that the conversion from IV to transdermal fentanyl can be accomplished safely and effectively using a 1:1 (IV:transdermal) conversion ratio and a two-step taper of the CII over 12 hours.