Effect of human atrial natriuretic peptide on blood pressure after sodium depletion in essential hypertension.

Human atrial natriuretic peptide was infused over four hours in three patients with essential hypertension. When the patients had a sodium intake of 200 mmol (mEq) daily an infusion of 0.5 micrograms atrial natriuretic peptide/min caused no significant change in blood pressure, whereas an infusion of 1.0 micrograms/min caused a gradual decrease in blood pressure and an increase in heart rate. After two to three hours of infusion with the higher dose two patients showed a sudden decrease in heart rate, with symptomatic hypotension. When the same patients had an intake of 50 mmol sodium daily their blood pressure was more sensitive to infusion of atrial natriuretic peptide; one patient again developed symptomatic hypotension, this time during an infusion of 0.5 micrograms/min. During all infusions distinct natriuresis occurred irrespective of whether blood pressure was affected. Prolonged, relatively low dose infusions of atrial natriuretic peptide can cause unwanted symptomatic hypotension. The effect on blood pressure is enhanced after sodium depletion, and blood pressure should be monitored carefully during longer infusions of atrial natriuretic peptide in patients with essential hypertension.