Inclusion Criteria:

• Hypertension, defined as a mean supine blood pressure greater than 140/90 mmHg and taking at least one (1) standard of care therapies (including a diuretic, angiotensin converting enzyme inhibitor or angiotensin receptor blocker and a calcium channel blocker).
• MDRD estimated GFR > 30 mL/min to be calculated at the screening visit by available serum creatinine.
• Male or female African Americans.
• Between the ages of 20 and 70 years.
• Have a body mass index (BMI) within the range of 18–40 kg/m ^2.
• Be able to communicate effectively with the study personnel.
• Be adequately informed of the nature and risks of the study and give written informed consent prior to receiving study medication

Exclusion Criteria:

• Known hypersensitivity or allergy to MANP or other natriuretic peptides.
• Women of child bearing age.
• Having received any investigational drug or device within 30 days prior to entry into the study.
• A history (within the last 2 years) of alcohol abuse, illicit drug use, significant mental illness, physical dependence to any opioid, or any history of drug abuse or addiction.
• A history of difficulty with donating blood or donated blood or blood products within 45 days prior to enrollment.
• Clinically significant new illness in the 1 month before screening in the opinion of the investigator.
• History of severe allergies.
• History of coronary artery. disease, cerebrovascular disease, or syncope.
• History of epilepsy or other seizure disorder.
• History of organ transplantation.
• Malignancy within 5 years.
• Clinically significant intrinsic renal disease, renal artery stenosis, or history of fibromuscular dysplasia of the renal arteries.
• Consumption of a phosphodiesterase-5 inhibitor.

Eligibility last updated 9/14/21. Questions regarding updates should be directed to the study team contact.