Fentanyl sublingual tablets (Abstral): An opioid analgesic for the management of breakthrough pain in cancer patients

In January 2011, fentanyl sublingual tablets were approved by FDA to manage breakthrough pain in patients aged ≥18 years who are already receiving and tolerant to opioids for their underlying persistent cancer pain. Abstral is not a generic version of fentanyl and patients should not be converted on a µg-per-µg basis from other fentanyl products.

Efficacy. Fentanyl transmucosal tablets' efficacy was investigated in a double-blind, placebo-controlled, crossover study enrolling opioid-tolerant (taking at least 60 mg of oral morphine daily, 25 µg transdermal fentanyl/hour, 30 mg of oral oxycodone daily, 8 mg oral hydromorphone daily or 25 mg oral oxymorphone daily, or an equianalgesic dose of another opioid for a week or longer) adult patients experiencing breakthrough cancer pain. One hundred thirty-one patients underwent open-label titration of fentanyl transmucosal tablets (dosing range: 100 µg to 800 µg) and 78 (60%) achieved adequate analgesia with tolerable side effects. Of these, 66 patients entered the double-blind treatment phase (with 60 completing the study). In these patients, the mean sum of pain intensity difference at 30 minutes (SPID30) for fentanyl transmucosal tablet-treated episodes was statistically significantly higher than for placebo-treated episodes.

Safety. The safety of fentanyl transmucosal tablets was evaluated in 311 opioid-tolerant cancer patients with breakthrough pain [270 were treated in multiple-dose studies with a duration of therapy averaging 131 days (range: 1–405 days) and with 44 patients treated for at least 12 months]. The most common adverse reactions observed during titration or maintenance phase (total frequency ≥3%) included nausea, somnolence, headache, and constipation. As with any opioid, serious or fatal respiratory depression can occur even at recommended doses and particularly in patients with underlying respiratory disorders (ie, chronic obstructive pulmonary disease), the elderly, or debilitated patients. The concomitant use of fentanyl transmucosal tablets with CYP3A4 isoenzyme inhibitors or inducers may result in alterations in fentanyl plasma concentrations. Dose adjustments may be required. Insufficient information exists to make recommendations regarding the use of fentanyl transmucosal tablets in patients with impaired renal or hepatic function.