Effect of Sublingual Dexmedetomidine vs Placebo on Acute Agitation Associated With Bipolar Disorder: A Randomized Clinical Trial

IMPORTANCE: Acute agitation is common in patients with bipolar disorder and requires urgent management to relieve distress and to prevent escalation to aggressive behavior. OBJECTIVE: To evaluate the effect of orally absorbed, sublingual dexmedetomidine, a selective α2A-adrenergic receptor agonist on symptoms of acute agitation in patients with bipolar disorder. DESIGN, SETTING, AND PARTICIPANTS: Phase 3, randomized, double-blind, placebo-controlled trial conducted in 15 sites in the US with enrollment between February 24, 2020, and April 27, 2020, and final follow-up on May 21, 2020. A total of 380 adults with bipolar I or II disorder were randomized and 362 completed the study. INTERVENTIONS: Participants were randomized to 3 groups: sublingual dexmedetomidine 180 μg (n = 127), sublingual dexmedetomidine 120 μg (n = 127), or placebo (n = 126). MAIN OUTCOMES AND MEASURES: The primary efficacy end point was the mean change from baseline at 2 hours for the Positive and Negative Syndrome Scale-Excited Component (PEC) total score. The range of possible total scores is 5 (absence of agitation) to 35 (extremely severe). The secondary end point was the earliest time of a statistically significant change in PEC total score from baseline for the drug vs placebo. On the primary efficacy end point, to account for multiplicity associated with comparing 2 sublingual dexmedetomidine doses with placebo, the 2-sided significance level for each dose vs placebo was set at .025. RESULTS: Of 380 patients randomized (mean age, 45.6 years; 54.8% women; and 56.1% Black individuals), 378 (99.5%) self-administered the study medication and completed the study. Baseline agitation was mild to moderate, with an overall mean PEC total score of 18.0. Two hours after taking the medication, the mean changes from baseline in PEC total score were −10.4 for sublingual dexmedetomidine 180 μg, −9.0 for sublingual dexmedetomidine 120 μg, and −4.9 for placebo. Least-square mean differences from placebo in the sublingual dexmedetomidine groups at 2 hours were −5.4 (97.5% CI, −6.6 to −4.2) for 180 μg and −4.1 (97.5% CI, −5.3 to −2.9) for 120 μg (both doses P