Review of fentanyl formulations in the management of breakthrough cancer pain

Breakthrough pain (BTP) has been commonly described as a transient exacerbation of pain that breaks through wellcontrolled persistent pain either spontaneously or in relation to a predictable trigger. The purpose was to summarize the evidence for dosing, frequency, definition of tolerance, and dose conversions between opioids in cancer patients administered various fentanyl ROO preparations. A literature search was conducted and 16 studies identified. Each definition varied but the majority classified BTP as a transient flare. The lowest OTFC starting dose of 200 mcg was used in all but two studies, 100 mcg for both sublingual and buccal preparations and 50mg for intranasal fentanyl. Six of the nine OTFC studies as well as the intranasal study also noted that patients should not receive more than four doses in a 24-hour period. The maximum number of doses of sublingual per day varied in each study. The most common symptoms regardless of the formulation were nausea, vomiting and constipation. BTP is a severe transitory pain that is sudden in onset and has a short duration. Many forms of fentanyl have been utilized in management of BTP. An entry dose of 60 mg of oral morphine was required in a majority of the studies and adverse events were as expected in patients medicated with opioids. The majority of patients required more than the minimum dose. Beginning treatment with larger doses would reduce the time to onset of pain relief. Future studies should investigate using larger doses in the prospective setting.