Analgesic effects of intranasal butorphanol tartrate administered via a unit-dose device in the dental impaction pain model: a randomized, double-blind, placebo-controlled, parallel-group study.

BACKGROUND: Butorphanol tartrate (BT) nasal spray is currently marketed as a multidose spray pump product. However, access to excessive amounts of drug in a single bottle (up to 15 doses) creates the potential for misuse, diversion, and abuse.

OBJECTIVE: This study evaluated the efficacy and tolerability of a sterile, unpreserved BT nasal spray administered via a unit-dose device in the treatment of moderate to severe pain after dental impaction surgery.

METHODS: This was a single-site, single-dose, randomized, double-blind, placebo-controlled, parallel-group pilot study of unit-dose BT nasal spray 1 and 2 mg compared with vehicle in patients who received standard anesthesia and underwent surgery to remove impacted third molars. When patients reported experiencing moderate or severe postoperative pain, they were assigned to receive the respective treatments in a 2:2:1 ratio. Patients rated pain intensity and pain relief and performed other assessments of analgesic efficacy before dosing and at 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 3, 4, and 6 hours after receipt of study medication. They could request rescue medication from 1 hour after the administration of nasal spray. The primary efficacy variables were summed pain intensity difference (SPID) at 2, 4, and 6 hours after administration of study medication and total pain relief at 6 hours (TOTPAR-6). Vital signs, pulse oximetry, and adverse events were monitored on the same schedule as pain assessments.

RESULTS: Thirty men and 30 women were enrolled (mean [SD] age, 22.5 [3.8] years; mean body weight, 168 [41.3] lb) and completed the trial. Pain relief was recorded in most patients within 15 minutes of receiving active treatment. A dose response was observed in SPID scores, with the 2-mg dose of BT providing the greatest response compared with placebo (P < 0.05). Overall, 52 (86.7%) patients requested rescue medication: 22 of 24 (91.7%) in the 1-mg group, 19 of 24 (79.2%) in the 2-mg group, and 11 of 12 (91.7%) in the placebo group. The time to use of rescue medication occurred a median of 75 to 110 minutes after nasal spray dosing. The analysis of TOTPAR-6 showed no significant differences overall or in pairwise comparisons. On the global assessment, 58.3% of patients in each of the active-treatment groups and 83.3% of patients in the placebo group evaluated the study drug as "poor." The unit-dose BT nasal spray was well tolerated, with central nervous system adverse effects being most common in the active-treatment groups compared with placebo (P = 0.029). Dizziness occurred in 11 (45.8%) patients who received BT 1 mg, 14 (58.3%) who received BT 2 mg, and 4 (33.3%) who received placebo; for headache, the corresponding numbers were 11 (45.8%), 7 (29.2%), and 2 (16.7%). There were no significant changes from baseline in vital signs, pulse oximetry, reported nasal irritation, or pathology (eg, irritation, epistaxis, ulceration).

CONCLUSIONS: In this small pilot study, sterile BT nasal spray administered via a unit-dose device provided effective postsurgical analgesia in approximately half of patients who had undergone surgery to remove impacted third molars. The results are similar to those of previous studies of BT nasal spray administered via multidose pump for postsurgical analgesia in the dental impaction pain model. The outcomes of this study are limited to the population studied.