Patients with
renal failure undergoing
hemodialysis often have
muscle cramps during and after the dialysis
therapy.
Muscle cramps are defined as the sudden onset of a prolonged involuntary muscle contraction accompanied with severe
pain, resulting in early termination of a HD session and inadequate dialysis. The etiology of the
cramps is unknown and effective anti-
cramp medicine is not available. We have hypothesized that water-soluble
vitamins are deficient in HD patients. Accordingly, we administrated
biotin to 14 patients who had frequent
muscle cramps during HD sessions.
Oral administration of 1 mg/day
biotin promptly reduced the onset and the severity of
cramps in 12 patients both during and after HD. Then, the plasma
biotin levels were measured by an
enzyme-linked
immunosorbent assay method (ELISA) in HD patients, including 14 patients with
cramps and 13 patients without
cramps, and 11 healthy volunteers. Plasma
biotin levels were elevated in 27 HD patients at baseline compared with healthy volunteers [451 (377 - 649) vs. 224 (148 - 308) ng/l, median (lower-upper quartiles); p < 0.0001]. Unexpectedly, among the 14
cramp patients, the
biotin levels were significantly higher in
biotin-ineffective 7 patients than
biotin-effective 7 patients [1,064 (710 - 1,187) vs. 445 (359 - 476) ng/l; p < 0.001]. Thus, the biotins measured by ELISA may consist of not only intact
biotin but also its metabolites that do not function as a
vitamin. In conclusion,
biotin administration is one choice to relieve HD patients from
muscle cramps regardless of their elevated plasma
biotin levels.