The administration of dexmedetomidine is limited to highly monitored care settings because it is only available for use in humans as intravenous medication. An oral formulation of dexmedetomidine may broaden its use to all care settings. The authors investigated the effect of a capsule-based solid oral dosage formulation of dexmedetomidine on sleep polysomnography.
Methods

The authors performed a single-site, placebo-controlled, randomized, crossover, double-blind phase II study of a solid oral dosage formulation of dexmedetomidine (700 mcg; n = 15). The primary outcome was polysomnography sleep quality. Secondary outcomes included performance on the motor sequence task and psychomotor vigilance task administered to each subject at night and in the morning to assess motor memory consolidation and psychomotor function, respectively. Sleep questionnaires were also administered.

Results

Oral dexmedetomidine increased the duration of non-rapid eye movement (non-REM) stage 2 sleep by 63 (95% CI, 19 to 107) min (P = 0.010) and decreased the duration of rapid eye movement (REM) sleep by 42 (5 to 78) min (P = 0.031). Overnight motor sequence task performance improved after placebo sleep (7.9%; P = 0.003) but not after oral dexmedetomidine–induced sleep (–0.8%; P = 0.900). In exploratory analyses, we found a positive correlation between spindle density during non-REM stage 2 sleep and improvement in the overnight test performance (Spearman rho = 0.57; P = 0.028; n = 15) for placebo but not oral dexmedetomidine (Spearman rho = 0.04; P = 0.899; n = 15). Group differences in overnight motor sequence task performance, psychomotor vigilance task metrics, and sleep questionnaires did not meet the threshold for statistical significance.

Conclusions

These results demonstrate that the nighttime administration of a solid oral dosage formulation of dexmedetomidine is associated with increased non-REM 2 sleep and decreased REM sleep. Spindle density during dexmedetomidine sleep was not associated with overnight improvement in the motor sequence task.

Editor’s Perspective
What We Already Know about This Topic
  • Dexmedetomidine is an alpha-2 adrenergic agonist sedative that is approved for intravenous use
  • A continuous infusion of dexmedetomidine promotes non–rapid eye movement stage 2 sleep neurophysiology
  • A single nighttime loading dose of intravenous dexmedetomidine in healthy volunteers promotes non–rapid eye movement stage 3 sleep neurophysiology
What This Article Tells Us That Is New
  • The hypothesis that oral dexmedetomidine would promote non–rapid eye movement stage 2 sleep was tested in a single-center, randomized, double-blind, crossover trial in 15 healthy volunteers
  • Oral dexmedetomidine increased the duration of non–rapid eye movement stage 2 sleep by 63 (95% CI, 19 to 107) min
  • Oral dexmedetomidine may impair sleep-dependent motor memory consolidation