A Short Term Open, Randomized Cross-over Trial Exploring the Effect of Carbonic Anhydrase Inhibition by Acetazolamide on Sleep Apnea Associated Hypertension and Vascular Dysfunction

Inclusion Criteria: * Provision of informed consent prior to any study specific procedures * Males 18 to 75 years * An Apnea-Hypopnea Index (AHI)\>15 and an Epworth Sleepiness Scale score (ESS)\>6 as verified by a PSG recording. * Patients with established hypertension (systolic/diastolic blood pressure \>= 160/95, either systolic or diastolic accounted for). * Clinically normal physical findings and laboratory values, as judged by the investigator * Body mass index \>= 35 kg/m2 Exclusion Criteria: * Hypersensitivity to sulfonamides or acetazolamide- * Patients with ongoing medication with other sulphonamides or patients any specific antihypertensive treatment. * History of severe allergy/hypersensitivity or ongoing allergy/hypersensitivity. * Subjects with a seizure disorder * Patients with clinically verified central sleep apnea * Clinically significant renal (serum creatinine \>2.0 mg/dL or \>130 micromol/L), neurological, metabolic (e.g. Type 1 or 2 diabetes), haematological or hepatic disease (ASAT or ALAT \>2 times the upper limit of normal). * Subjects with an occupational risk potentially exaggerated by daytime sleepiness such as handling complex machinery or professional driving * Unstable angina pectoris, unstable hypertension (or poorly controlled diabetes (HbA1C \< 52 mmoles/mol, or fasting plasma glucose \>7 mmoles/l). * Clinically significant congestive heart failure. * Myocardial infarction or coronary vessel intervention within the previous 6 months period. * Subjects with uncontrolled hypertension (defined as a diastolic blood pressure ≥110 mmHg and/or a systolic blood pressure ≥180 mmHg with or without medication). * Previously diagnosed or treated clinically significant cardiac arrhythmia * Clinically significant chronic pulmonary or gastrointestinal disease. * Clinical history of depression as judged by the investigator or other previous or present clinically significant psychiatric disease * Suspected or confirmed poor compliance * Alcohol or drug abuse during the last year. * Subjects with any other significant condition that, in the opinion of the investigator, could interfere with participation in the study. * Severe nocturnal hypoxia defined as more than 10 episodes with an oxygen desaturation exceeding 50% or signs of lacking resaturation between desaturations on previous recordings according to investigators judgment * Participation in another clinical study during the last 6 months. * Inability to understand and complete the questionnaires.