Patients with opioid use disorder treated with either methadone or buprenorphine are at risk of developing central sleep apnea (CSA) from these medications. Investigators will conduct a mechanistic trial using acetazolamide, a medicine known to improve CSA in other settings, to determine if acetazolamide can improve CSA due to medication for opioid use disorder and whether this leads to physiologic changes that might lead to reduced drug craving. Patients treated with medication for opioid use disorder and who have central sleep apnea will be randomized to treatment with acetazolamide or matching placebo for 7 days. At the end of the 7 days, they will undergo an overnight sleep study to assess the impact on breathing during sleep as well as sleep quality. In addition, measures of sympathetic tone, anxiety, arousal, cognition, and drug craving will be measured to determine if treatment of CSA with acetazolamide can produce physiologic changes that might contribute to improved health.