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Safety and tolerability of high doses of intrathecal fentanyl for the treatment of chronic pain.

Fentanyl is commonly used systemically or neuraxially for the management of chronic pain. It can be administered intrathecally via implanted pump, but it is generally considered only after trials of intrathecal (IT) morphine and hydromorphone have proven ineffective. Published experience with IT fentanyl is limited, and long-term therapy at relatively high doses has not been described previously. We describe four patients who were treated with IT fentanyl after other analgesic approaches had failed and who gradually underwent dose escalation to levels as high as 20 times those previously reported. Safety and tolerability were maintained during dose titration. Our experience highlights an expanding scope of practice in the use of IT opioids in general and fentanyl specifically and suggests that high-dose fentanyl can be used safely in highly selected patients.