Is reducing sympathetic activity with clonidine beneficial in heart failure?
Several studies have shown that sympathetic activation has a negative effect on survival in congestive heart failure (e.g., see Kaye DM, et al, J Am Coll Cardiol 1995;26:1257). It follows that inhibition of sympathetic activity might be beneficial. This study measured the effect of relatively short-term (2 month) administration of clonidine (transdermal patch, 0.2 mg/d) or placebo patch given in addition to standard treatment with furosemide and enalapril. Patients did not receive either β-blockers or aldosterone antagonists. Clonidine reduced plasma norepinephrine by 47% and muscle sympathetic nerve activity (MSNA) by 27%. No significant change in heart rate or blood pressure were observed. Cardiac baroreflex (heart rate) and sympathetic baroreflex (MSNA) responses to changes in blood pressure were not altered by clonidine. In conclusion, clonidine was effective in reducing sympathetic activity. This was not associated with changes in blood pressure, heart rate or baroreflex function.
