LOW-DOSE PRAZOSIN IN PATIENTS WITH MUSCLE CRAMPS DURING HEMODIALYSIS

Sympathetic nervous system response to volume stress is more marked in patients with frequent hemodialysis-associated skeletal muscle cramps than in most patients who cramp infrequently. Accordingly, we conduct ed a double-blind, randomized, and balanced trial in which five patien ts with frequent hemodialysis-associated cramps were given either plac ebo or a prazosin dose (ranging from 0.25 to 1.0 mg) at the start of 1 6 dialysis sessions. These low doses of prazosin appeared to reduce cr amp frequency in four of the five patients, and patient-stratified mul tiple logistic regression analysis indicated an aggregate 58% reductio n in cramp frequency (p = 0.030). On the other hand, prazosin therapy was associated with an increased incidence of hypotension that require d therapeutic intervention both during (p = 0.033) and after (p = 0.01 0) hemodialysis. Our findings support the hypothesis that sympathetic activation plays a pathogenetic role in hemodialysis-associated skelet al muscle cramps and suggest that pharmacologic attenuation of this re sponse may be of therapeutic benefit.