The investigators hypothesis is that obstructive sleep apnea (OSA) patients with a low arousal threshold may wake up too early during a respiratory event, before upper airway muscles can be activated to achieve stable ventilation. Thus, strategies to manipulate the respiratory arousal threshold could potentially improve the quality of sleep and sleep disordered breathing. Agents that raise arousal threshold are therefore likely to benefit some patients with OSA. The overall goal of this project is to determine the importance of the arousal threshold in OSA, determine which patients might benefit from a raised arousal threshold, and test this hypothesis by using pharmacological manipulation of the arousal threshold to achieve this goal.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
20
Venlafaxine 50mg before sleep
One piece of placebo before sleep
University of California, San Diego
San Diego, California, United States
The Apnea Hypopnea Index
The Apnea hypopnea index is an index used to indicate the severity of sleep apnea. It is represented by the number of apnea and hypopnea events per hour of sleep. The change from baseline in apnea hypopnea index after a single dose of Venlafaxine will be evaluated using overnight polysomnography. An apnea hypopnea index less than five events per hour is considered within normal limits.
Time frame: Baseline and 7-day follow up
Nadir Oxygen Level During Sleep
Change from baseline in nadir oxygen level during sleep after a single dose of Venlafaxine will be evaluated using overnight polysomnography. A lower blood oxygen saturation during sleep is associated with a more severe obstructive sleep apnea.
Time frame: Baseline and 7-day follow up
Loop Gain
Loop gain 1 is used to describe the stability of ventilatory control. The change from baseline in loop gain after a single dose of Venlafaxine will be estimated.
Time frame: Baseline and 7-day follow up
Arousal Threshold
Change from baseline in respiratory arousal threshold after single dose of Venlafaxine will be estimated.
Time frame: Baseline and 7-day follow up
Sleep Efficiency
Change from baseline in sleep efficiency after single dose of Venlafaxine will be estimated using overnight polysomnography.
Time frame: Baseline and 7-day follow up
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