The Impact of Venlafaxine on Apnea Hypopnea Index in Obstructive Sleep Apnea

This study is a randomized double-blinded crossover pilot study. The investigators will test whether Venlafaxine has important effects on the apnea hypopnea index. Venlafaxine is a serotonin-norepinephrine reuptake inhibitor (SNRI) for the treatment of depression and anxiety. Venlafaxine increases serum serotonin level, which may affect arousal threshold. Furthermore, higher serotonin level theoretically may improve muscle tone, including upper airway muscle. Therefore, the investigators hypothesize that venlafaxine may decrease arousal threshold and improve muscle tone, leading to improvement of OSA. Eligible participants will undergo overnight polysomonography as described below and will receive either Venlafaxine(50 mg 2 hour prior to sleep) or placebo (in random order) followed roughly 7 days later with placebo or donepezil. This aim will allow us to test the impact of Venlafaxine on the apnea hypopnea index. The change in apnea hypopnea index will be compared in the Venlafaxine groups with the placebo group.