There is an increased risk for sleep disordered breathing (SDB), sleep-related hypoventilation and irregular breathing in individuals on chronic prescription opioid medications. Almost 30% of a veteran sleep clinic population had opioid-associated central sleep apnea (CSA). The proposal aims to identity whether oxygen and acetazolamide can be effective in reducing unstable breathing and eliminating sleep apnea in chronic opioid use via different mechanisms. We will study additional clinical parameters like quality of life, sleep and pain in patients with and without opioid use. This proposal will enhance the investigators' understanding of the pathways that contribute to the development of sleep apnea with opioid use. The investigators expect that the results obtained from this study will positively impact the health of Veterans by identifying new treatment modalities for sleep apnea.