Sublingual fentanyl citrate for cancer-related breakthrough pain: a pilot study

The effects of sublingual fentanyl citrate (SLFC) were assessed in 11 hospice inpatients with cancer-related breakthrough pain. Patients were asked to rate their pain, using a visual analogue scale, before SLFC, then after 3, 5, 10, 15, 30, 45 and 60 min. Six patients (55%) had reductions in pain scores at 10 min and nine patients (82%) at 15 min. Ratings for SLFC were very good (18%), good (36%), moderate (28%), and bad (18%). Compared to the usual breakthrough medication, SLFC was better (46%), the same (36%), or worse (18%). Advantages of SLFC included ease of use, quick onset of action and no associated drowsiness. No systemic adverse events were noted, but two patients reported dry mouth and two a bitter taste. Two patients found it difficult to retain the medication under the tongue. Seven patients (64%) said they would continue to use SLFC. Sublingual fentanyl citrate appears safe and well tolerated by these patients. Randomized placebo-controlled and dose ranging studies are required to confirm these findings.