title: A multicenter, randomized, double-blind, parallel-group trial of the antihypertensive efficacy and tolerability of a combination of once-daily losartan 100 mg/hydrochlorothiazide 12.5 mg compared with losartan 100-mg monotherapy in the treatment of mild to severe essential hypertension.
abstract: BACKGROUND
  Because patients with hypertension may require >1 antihypertensive agent to control blood pressure (BP), physicians often prescribe a fixed combination of antihypertensive medications.
  
  
  OBJECTIVE
  This study evaluated the effect of adding low-dose hydrochlorothiazide 12.5 mg (HCTZ12.5) to high-dose losartan 100 mg (L100) in patients with hypertension whose BP was inadequately controlled with L100 monotherapy.
  
  
  METHODS
  Enrolled in this multicenter, randomized, double-blind, parallel-group, filter study were patients aged > or =18 years with a mean trough sitting diastolic BP (SiDBP) of 95 to 120 mm Hg. Patients were treated with L100 QD for 4 weeks. Patients who did not achieve adequate BP control were randomly assigned to receive L100/HCTZ12.5 or L100 QD for 6 weeks. The primary efficacy measure was the mean change in trough SiDBP from baseline in the 2 groups. Responders were defined as patients with a mean trough SiDBP of <90 mm Hg or patients who had a > or =10-mm Hg decrease in mean trough SiDBP.
  
  
  RESULTS
  Demographic characteristics were similar between treatment groups. The patients randomized to the double-blind treatment period were mostly white (65.1%) and male (57.5%), with a mean age of 53.8 years. The mean (SD) duration of hypertension at baseline was 9.7 (8.5) years. The proportion of patients previously treated with antihypertensive therapy was 76.7%. Of the 367 patients enrolled in the L100 filter period, 292 patients had BP inadequately controlled with L100 monotherapy and were randomized to receive L100 (n = 145) or L100/HCTZ12.5 (n = 147). At week 6 after randomization, mean trough SiDBP was significantly lower in the L100/HCTZ12.5 group than in the L100 group (-8.3 vs -5.2, respectively; P < 0.001). The between-group difference was -3.0 mm Hg (95 % CI, -4.6 to -1.40; P < 0.001), and the proportion of responders was significantly greater in the L100/HCTZ12.5 group than in the L100 group (63.0% vs 44.4%; P < 0.001). The incidence of adverse events (AEs) occurring in >2% of patients during the double-blind period was similar for both groups. AEs occurring in the L100 group and the L100/HCTZ12.5 group included respiratory tract infection (6.2% vs 3.4%, respectively), dizziness (2.1% vs 0.7%), and headache (0.7% vs 3.4%).
  
  
  CONCLUSIONS
  After 6 weeks of therapy, L100/HCTZ12.5 was associated with greater antihypertensive efficacy than L100, as measured by the change in mean trough SiDBP The percentage of responders was significantly greater in the L100/HCTZ12.5 group than in the L100 group.
authors.affiliation: Merck Research Laboratories, Merck & Co., Inc., Blue Bell, Pennsylvania, USA. gilbert_gleim@merck.com
authors.forename: Gilbert W
authors.initials: GW
authors.lastname: Gleim
authors.forename: Joseph
authors.initials: J
authors.lastname: Rubino
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zhang
authors.forename: Shahnaz
authors.initials: S
authors.lastname: Shahinfar
authors.forename: Beth A
authors.initials: BA
authors.lastname: Soffer
authors.forename: Paulette A
authors.initials: PA
authors.lastname: Lyle
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Littlejohn
authors.forename: Peter U
authors.initials: PU
authors.lastname: Feig
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D006852:Hydrochlorothiazide / Q000008:administration & dosage / Q000627:therapeutic use*; D019808:Losartan / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D000959:Antihypertensive Agents; D006852:Hydrochlorothiazide; D019808:Losartan