title: Plasma renin activity and plasma concentrations of norepinephrine and cyclic nucleotides in heart failure after prazosin.
abstract: A single oral dose of 1.0 to 2.0 mg prazosin was given to 14 patients with congestive heart failure to assess its effect. Prazosin increased cardiac index (+27.5%) and decreased pulmonary arterial diastolic pressure (-29.1%), systemic vascular resistance (-27.7%), mean blood pressure (-11.8%), and double products (-12.9%). Plasma renin activity (¿.8%) and plasma concentrations of norepinephrine (+67.5%) and cyclic adenosine monophosphate (AMP) (+10.6%) rose. There was a negative correlation between plasma cyclic AMP concentration and the increase of plasma cyclic AMP concentration after prazosin (Y = -0.53X + 18.7). There were no changes in heart rate and plasma cyclic guanosine monophosphate concentration. The effects were maximum at 3 hr and lasted 5 hr. The results indicate that oral prazosin has a beneficial hemodynamic effect in patients with congestive heart failure, and that the pathologic effects of prazosin, "alpha-blocker." induces a rise in plasma renin activity as well as in plasma concentrations of norepinephrine and cyclic AMP.
mesh_terms: D000328:Adult; D000368:Aged; D000242:Cyclic AMP / Q000097:blood; D006152:Cyclic GMP / Q000097:blood; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000188:drug therapy*; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D011224:Prazosin / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*; D012083:Renin / Q000097:blood
chemical_list: D011799:Quinazolines; D000242:Cyclic AMP; D012083:Renin; D006152:Cyclic GMP; D009638:Norepinephrine; D011224:Prazosin