Background: The treatments of obstructive sleep apnea (OSA) consist of surgical such as uvulopalatopharyngoplasty and
non-surgical approaches such as continuous positive airway pressure (CPAP), weight reduction, dental appliance, and some
medications. Cholinergic nerve system has been shown an important role in respiratory regulation and in sleep apnea.
Donepezil, a reversible acetylcholine esterase inhibitor, can increase cholinergic nerve activity especially during sleep. There
were some studies on the efficacy of donepezil in treatment of OSA patients and found significant improvement in the apneahypopnea index (AHI) and oxygen saturation compared to pretreatment and placebo.
Objective: To evaluate the efficacy of donepezil in the treatment of obstructive sleep apnea (OSA).
Material and Method: A prospective, randomized study was conducted at HRH Princess Maha Chakri Sirindhorn Medical
Center. OSA patients diagnosed by polysomnography and Epworth Sleepiness Scale scores were randomly allocated into
study group and control group. The study group received donepezil (5 mg), 1 tablet a day for 4 weeks then increased to 2
tablets a day for the next 4 weeks. The control group received placebo drug in the same doses. The value of apnea-hypopnea
index (AHI), minimum oxygen saturation (minimum SpO2) and Epworth Sleepiness Scale scores were used in comparison both before and after the end of the study.
Results: At the end of the study, 41 patients were collected of which 21 patients were in study group and 20 patients were
in control group. Before treatment, there were no significant difference in age (p = 0.53), body mass index (p = 0.80), sex
(p = 0.44), minimum SpO2 (p = 0.36), Epworth sleepiness Scale scores (p = 0.86), and AHI (p = 0.06) between two groups. After treatment, no statistically significant difference in the value of AHI, minimum SpO2 and Epworth Sleepiness Scale scores were identified both in the same group and between two groups (p>0.05).
Conclusion: Treatment OSA patients with donepezil did not show better results than placebo.

Keywords: Obstructive Sleep Apnea, Donepezil