Effects of sustained-release moxonidine, an imidazoline agonist, on plasma norepinephrine in patients with chronic heart failure.
BACKGROUND
In chronic heart failure, sympathetic activation is increased. Moxonidine acts on central nervous system receptors to decrease sympathetic activation. We investigated the dose-response relationship of a new sustained-release (SR) preparation of moxonidine and the plasma concentration of norepinephrine in patients with chronic heart failure.


RESULTS
A total of 268 patients with chronic heart failure in NYHA functional class II to IV on optimal standard therapy were randomized to placebo or 1 of 5 doses of moxonidine SR: 0.3, 0.6, 0.9, 1.2, or 1.5 mg BID. After a dose-titration phase (7 weeks), patients were followed up for another 12 weeks at their maximally tolerated dose. Blood samples for plasma norepinephrine were collected at baseline and weekly during the initial 7 weeks, at week 19, and at the end of the study. At baseline and 7 and 19 weeks, sampling was also done 4 hours after the dose. After the active phases of the study, plasma norepinephrine was evaluated for an additional 3 days. A marked, statistically significant dose-related decrease in plasma norepinephrine was observed for predose levels as well as 4 hours after the dose at week 19. At the highest dose (1.5 mg BID), the trough reduction in norepinephrine was 52%. These reductions were accompanied by a modest decrease in heart rate, a modest increase in left ventricular ejection fraction, and a dose-related increase in adverse events.


CONCLUSIONS
Plasma norepinephrine was markedly reduced in a dose-related manner by moxonidine SR. This reduction was accompanied by evidence of reverse remodeling, but also by an increase in adverse events.
Swedberg
Karl
K
Department of Medicine, Sahlgrenska University Hospital/Ostra, Göteborg, Sweden. karl.swedberg@hjl.gu.se
Bristow
Michael R
MR
Cohn
Jay N
JN
Dargie
Henry
H
Straub
Matthias
M
Wiltse
Curtis
C
Wright
Theressa J
TJ
D001794:Blood Pressure / Q000187:drug effects; D002908:Chronic Disease; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood*; D013565:Sympatholytics / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D018487:Ventricular Dysfunction, Left / Q000188:drug therapy
D003692:Delayed-Action Preparations; D007093:Imidazoles; D013565:Sympatholytics; C043482:moxonidine; D009638:Norepinephrine