Managing Opioid Related Sleep Apnea With Acetazolamide

Inclusion Criteria: * Age 18+ * Chronic pain * Chronic opioid use (daily use for \>3 months duration) with \>/= 20 oral Morphine Equivalent Dose (MEqD) per day * Apnea-hypopnea index \>/= 10 events/hr (hypopnea definition: ≥ 3% desaturation or arousal criteria per American Academy of Sleep Medicine 2012 scoring rules) Exclusion Criteria: * Use of opioids outside medical supervision (e.g. recreational use) * Unable or unwilling to withhold any ongoing SDB treatment (e.g. CPAP) for the duration of the study * Urgent need to initiate effective SDB therapy * Chronic lung disease (other than well-controlled asthma) * Active cardiac disease including heart failure, chest pain, or heart rhythm problems * Neurological or developmental problems affecting breathing * Major sleep disorders other than sleep apnea * Chronic kidney disease * Cirrhosis of the liver * Active cancer treatment or limited life expectancy * Psychiatric disease other than controlled mood disorders * Use of diuretics, potassium supplementation, or medications that may affect potassium * Allergy to study drug or related compounds including sulfa drugs * Know electrolyte disturbances * Hospitalized in the last 90 days or anticipated hospitalization within 3 months * Alcohol use \>2 standard drinks per day * Presence of tracheostomy or artificial airway * Prisoners * Pregnancy or anticipating pregnancy in next 2 months, or nursing * Unable or unwilling to provide informed consent * Unable to follow study protocol