title: The effect of antihypertensive agents on sleep apnea: protocol for a randomized controlled trial.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) and hypertension are well-known cardiovascular risk factors. Their control could reduce the burden of heart disease across populations. Several drugs are used to control hypertension, but the only consistently effective treatment of OSA is continuous positive airway pressure. The identification of a drug capable of improving OSA and hypertension simultaneously would provide a novel approach in the treatment of both diseases.
  
  
  METHODS
  This is a randomized double-blind clinical trial, comparing the use of chlorthalidone with amiloride versus amlodipine as a first drug option in patients older than 40 years of age with stage I hypertension (140 to 159/90 to 99 mmHg) and moderate OSA (15 to 30 apneas/hour of sleep). The primary outcomes are the variation of the number of apneas per hour and blood pressure measured by ambulatory blood pressure monitoring. The secondary outcomes are adverse events, somnolence scale (Epworth), ventilatory parameters and C reactive protein levels. The follow-up will last 8 weeks. There will be 29 participants per group. The project has been approved by the ethics committee of our institution.
  
  
  CONCLUSIONS
  The role of fluid retention in OSA has been known for several decades. The use of diuretics are well established in treating hypertension but have never been appropriately tested for sleep apnea. As well as testing the efficacy of these drugs, this study will help to understand the mechanisms that link hypertension and sleep apnea and their treatment.
  
  
  BACKGROUND
  ClinicalTrials.gov: NCT01896661.
authors.forename: Fábio Tremea
authors.initials: FT
authors.lastname: Cichelero
authors.forename: Denis
authors.initials: D
authors.lastname: Martinez
authors.forename: Sandra Costa
authors.initials: SC
authors.lastname: Fuchs
authors.forename: Miguel
authors.initials: M
authors.lastname: Gus
authors.forename: Leila Beltrami
authors.initials: LB
authors.lastname: Moreira
authors.affiliation: Postgraduate Studies Program in Cardiology, School of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. ffuchs@hcpa.ufrgs.br.
authors.forename: Flávio Danni
authors.initials: FD
authors.lastname: Fuchs
mesh_terms: D000328:Adult; D017311:Amlodipine / Q000009:adverse effects / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D018660:Blood Pressure Monitoring, Ambulatory; D002121:Calcium Channel Blockers / Q000009:adverse effects / Q000627:therapeutic use*; D002752:Chlorthalidone / Q000009:adverse effects / Q000627:therapeutic use*; D002985:Clinical Protocols; D004232:Diuretics / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D017286:Polysomnography; D012107:Research Design; D012890:Sleep / Q000187:drug effects; D012891:Sleep Apnea Syndromes / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D004232:Diuretics; D017311:Amlodipine; D002752:Chlorthalidone