Carvedilol does not modulate moderate exercise-induced hyperkalemia in hemodialysis patients.
OBJECTIVE
Non-selective beta-adrenergic blockers may cause hyperkalemia in patients with end-stage renal failure. In contrast, alpha-adrenergic blockade has been found to decrease the hyperkalemic effect of physical exercise in healthy subjects, although we were unable to confirm this effect in hemodialysis patients. In a crossover design, we studied the effect of carvedilol, a non-selective beta-adrenergic blocker with an additional alpha1-blocking activity, on exercise-induced hyperkalemia in 17 anuric hemodialysis patients.


METHODS
All subjects were given either carvedilol (25 mg/day) or placebo for 2 weeks in a random order with a 2-week wash-out period. At the end of each treatment period they underwent a 30-minute exercise test on a bicycle ergometer with a fixed load of 20 W.


RESULTS
The treatment with carvedilol caused a significant decrease in blood pressure. Serum potassium before exercise tests was similar (5.37 +/- 0.2 and 5.24 +/- 0.2 mmol/l on carvedilol and placebo, respectively; mean +/- SE). During the exercise, serum potassium increased significantly (p < 0.001 in both tests) and subsequently decreased during 30 minutes of recovery (p < 0.05). The mean rate of potassium increment during the exercise was similar (23.3 +/- 3.3 micromol/l/min on carvedilol and 20.0 +/- 3.6 micromol/l/min on placebo). During recovery, the mean rate of potassium decrement was 5.0 +/- 3.0 micromol/l/min and 6.7 +/- 2.7 micromol/l/min, respectively. Serum sodium, ionized calcium, insulin and plasma renin activity were similar before the exercise tests and did not change during the exercise.


CONCLUSIONS
Carvedilol does not enhance the hyperkalemic effect of moderate physical exercise in anuric hemodialysis patients.
Nowicki
M
M
Department of Nephrology, Endocrinology and Metabolic Diseases, Silesian University School of Medicine, Katowice, Poland. nefro@wp.pl
Szewczyk-Seifert
G
G
Klimek
D
D
Kokot
F
F
D000317:Adrenergic alpha-Antagonists / Q000009:adverse effects / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000009:adverse effects* / Q000494:pharmacology; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D002227:Carbazoles / Q000009:adverse effects* / Q000494:pharmacology; D000077261:Carvedilol; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006947:Hyperkalemia / Q000097:blood / Q000209:etiology*; D008297:Male; D011188:Potassium / Q000097:blood; D011412:Propanolamines / Q000009:adverse effects* / Q000494:pharmacology; D006435:Renal Dialysis
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D011188:Potassium