ANP is cleared much faster than BNP in patients with congestive heart failure

To obtain a better understanding of the pharmacokinetics of atrial and brain natriuretic peptides (ANP and BNP, respectively), two peptide mediators used in the treatment of congestive heart failure (CHF). Although both peptides exert their effects by binding to a common receptor (natriuretic peptide receptor A) with about the same affinity, their respective loading and maintenance doses differ.

Sixteen CHF patients were randomized to be infused for 2 h with alpha-human ANP (0.05 microg/kg per minute) or BNP (0.01 microg/kg per minute). Plasma concentrations of both peptides were measured 0, 2, 5, 15, 30, 60 and 120 min post-infusion. The pharmacokinetic parameters were then calculated using a 1-compartment model.

The plasma BNP concentrations in the ANP and BNP groups before infusion were 464.7 +/- 339.8 and 506.8 +/- 332.5 pg/ml, respectively. Following infusion, ANP disappeared from the circulation more rapidly than BNP: their plasma half-lives were 2.4 +/- 0.7 and 12.1 +/- 3.0 min, and their total body clearance volumes were 48.2 +/- 24.1 and 10.1 +/- 2.7 ml/min per kilogram, respectively.

ANP has a shorter half-life in the plasma of CHF patients than BNP, which suggests that it controls hemodynamics more readily than BNP.