to investigate the mechanism of pharmacodynamic tolerance reported to occur during prazosin therapy of chronic congestive heart failure , we measured plasma norepinephrine , plasma epinephrine , plasma renin activity ( pra ) and plasma aldosterone , as well as hemodynamics in eight patients with chronic congestive heart failure , functional class iii and iv ( nyha ) , before and during 10 weeks of prazosin therapy .
C0028351
norepinephrine
C0014563
epinephrine