Activation of renin-angiotensin system does not cause skeletal muscle cramps during hemodialysis.
Activation of the renin-angiotensin system usually occurs during hemodialysis and in hemodialyzed normal dogs parallels reductions in blood flow to a tissue group that is largely composed of skeletal muscle. To determine if excessive activation of this system might cause dialysis-associated skeletal muscle cramps in some patients, we conducted a double-blind, randomized and balanced trial in which 5 patients with frequent dialysis-associated cramps were each given either a 25 mg oral dose of captopril or placebo 1 h before 8 consecutive dialyses. Captopril increased the frequency of dialyses complicated by skeletal muscle cramps in 1 patient and did not affect cramp frequency in the other 4 patients. Predialysis plasma renin activity (PRA) averaged 3.9 ng/ml/h (+/- SD) and was the same as in unselected hemodialysis patients. Following captopril, PRA increased by an average of 2.2 +/- 0.7 times, similar to the 2.6-fold increase that was reported when this drug was used to prevent dialysis-associated hypertensive crises. However, hemodialysis by itself did not activate the renin-angiotensin system as consistently in patients with frequent dialysis-associated skeletal muscle cramps as in unselected hemodialysis patients and the ratio of post- to predialysis PRA averaged 1.0 +/- 0.6. We conclude that the renin-angiotensin system does not mediate, and that its activation during hemodialysis may actually help prevent, dialysis-associated skeletal muscle cramps.
Piergies
A A
AA
Department of Medicine, Northwestern University Medical School, Chicago, IL.
Atkinson
A J
AJ
Hubler
G L
GL
del Greco
F
F
D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002216:Captopril / Q000009:adverse effects / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007444:Inulin / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D009120:Muscle Cramp / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D006435:Renal Dialysis / Q000009:adverse effects*; D012083:Renin / Q000097:blood*; D012084:Renin-Angiotensin System / Q000502:physiology*; D013997:Time Factors; D014508:Urea / Q000493:pharmacokinetics
D014508:Urea; D007444:Inulin; D002216:Captopril; D012083:Renin