Background: Data on the treatment of breakthrough cancer pain (BTcP) in patients receiving methadone therapy are lacking. Whether methadone produces tolerance to other opioids, other opioids should be less effective when administered as a BTcP medication.
Aim: The aim of this preliminary study was to assess the efficacy of fentanyl buccal tablets (FBT) for the treatment of BTcP in patients who receive methadone as a background analgesic.
Patients and methods: A prospective study was carried out for a period of 1 year in a consecutive sample of 13 advanced cancer patients admitted to an acute pain relief and palliative care unit-patients who were receiving stable doses of oral methadone for their background analgesia. The dose of FBT was 100 μg for patients who were receiving 12 mg of oral methadone. For higher doses of methadone, proportional doses of FBT were given. For each episode, trained nurses collected changes in pain intensity (on numerical scale 0-10) and emerging problems when called for pain increases considered to be severe in intensity by patients) (T0) and 15 min after FBT administration (T15).
Results: The mean age was 58.1 (SD 9.9), and nine patients were males. Sixty-four events were treated with FBT (4.9 ± 3.1 for each patient, on average). Patients were receiving mean doses of oral methadone of 68 mg (range 15-240). In the majority of events, a decrease in pain intensity >33% and >50% was observed (n = 20 and n = 26, respectively), 15 min after the administration of FBT. Data on ten episodes were unavailable. Nine events were unsuccessfully treated. In all the patients, the level of adverse effects after FBT administration was mild and undistinguishable from that associated with basal opioid analgesia.
Conclusion: FBT was effective as breakthrough pain medication in patients receiving methadone for their background analgesia, confirming that this group of patients are not inevitably resistant to other opioids.