Study hypothesis is that the time from randomization to the increase of natriuresis (%), time to standardization of natriuresis daily profile, blood pressure profile and the percentage reduction of central hemodynamic parameters will be relatively changed over the study period by more than 15%.

Inclusion Criteria:

1. Men and women in the age from 40 to 70 years.
2. Established diagnosis of II-III grade essential arterial hypertension
3. NYHA II-III chronic heart failure
4. Salt-sensitivity
5. Stable therapy for 3 months prior enrollment to the study including any diuretic, ACE-inhibitor, beta-blocker.
6. Signed informed consent for participation in the study.
7. Women with child-bearing potential should agree to use effective birth control methods from screening up to completion of the study, excluding situations when their sexual partner(s) are surgically sterilized, or whеn women do not have any sexual contacts. Effective methods of birth control are contraception methods which are used constantly and regularly (including implantable contraceptives, injectable contraceptives, oral contraceptives, transdermal contraceptives, intrauterine devices, diaphragms with spermicides, male or female condoms or cervical cap).

Exclusion Criteria:

1. Unlikely cooperation with a patient in the study period, disability
2. Identification of salt - resistance at screening
3. Patients that have had myocardial infarction, unstable angina pectoris, percutaneous coronary intervention heart failure, hypertensive encephalopathy, cerebrovascular accident (stroke) or transient ischaemic attack for the last 3 months.
4. Patients with severe heart failure (Stage IV of New York Heart Association), clinically significant aortic valve or mitral stenosis, uncorrected coarctation of the aorta, obstruction of cardiac output (obstructive hypertrophic cardiomyopathy)
5. Previous glomerulonephritis, severe pyelonephritis or another known severe renal disease which is confirmed by GFR < 40 ml/min/1.73 m2 calculated by Cockroft-Gault formula.
6. Secondary arterial hypertension, severe or uncontrolled AH at the study enrollment (BP> 180 mm Hg or DAP > 110 mm Hg)
7. Any severe, decompensated or unstable diseases or conditions which, on the investigator's opinion, endanger patient's life or aggravate disease prognosis (decompensated heart failure, anemia, severe diabetes mellitus, autoimmune, oncological diseases, hepatic, allergic reactions, connective tissue diseases, etc.)
8. Acute infectious diseases.
9. Hypersensitivity to components of Britomar or Diuver
10. Pregnancy, lactation period.
11. Participation in another clinical study for the last 30 days.
12. Scheduled coronary artery surgery (for example, stent implantation or coronary artery bypass grafting) or any other non-cardiological major surgery.
13. 13. Administration of drugs which affect natriuresis level (any diuretics which are not related with the study product). Patients are excluded from the study if they have taken the drugs for the last 48 years up to Visit D -10, in the screening period and/or treatment period/follow-up period of the study.
14. Use of narcotic drugs or alcohol abuse for the last 6 months and inability/unwillingness to refrain from narcotic drugs and excessive alcohol intake in the study period. The excessive alcohol intake is average alcohol >2 units of alcohol. A unit of alcohol for various beverages is 12 ounce (350 ml) of beer, 5 ounce (150 ml) of wine or 1.5 ounce (45 ml) of 80% alcohol.
15. Any other reason which would hinder patients' compliance with study requirements or their understanding of the study aim and potential risks of participation in study.