Vitamin B supplementation for leg cramps during pregnancy. Magnesium for the treatment of nocturnal leg cramps: a crossover randomized trial. Randomised, cross-over, placebo controlled trial of magnesium citrate in the treatment of chronic persistent leg cramps. The effect of oral magnesium substitution on pregnancy-induced leg cramps. The effect of magnesium infusion on rest cramps: randomized controlled trial. Does oral magnesium substitution relieve pregnancy-induced leg cramps?
nan Nocturnal leg cramps are a common health problem in the ambulatory setting. Our objective was to evaluate the efficacy of magnesium in the treatment of nocturnal leg cramps.
                Our study was a crossover randomized double-blind placebo-controlled trial. We included patients from a large university-based ambulatory clinic in Buenos Aires, Argentina, with at least 6 cramps during the previous month. A total of 93 subjects took part in a 4-week washout period with placebo. Those who were still eligible (n = 45) were randomized to receive either (1) an oral dose of 900 mg magnesium citrate twice daily for 1 month, followed by a matching placebo for 1 month, or (2) the placebo first, followed by magnesium. Both groups had a 4-week washout period with placebo between each treatment month. Forty-two patients completed the 4-month study. The main outcome was the number of nocturnal leg cramps, and the secondary outcomes were duration, severity, and sleep disorders caused by those cramps.
                There were no significant differences between magnesium and placebo in any of the evaluated outcomes. The mean number of cramps was 11.1 (standard deviation [SD] +/- 7.3) for placebo versus 11.8 (SD +/- 7.6) for magnesium (P = .59). We observed a significant period-effect bias: All patients improved over time regardless of the treatment sequence they received.
                Magnesium was not effective for the treatment of nocturnal leg cramps. The period-effect bias probably occurred because of a combination of the natural history of this condition, a regression to the mean, and a true placebo effect. Nocturnal leg cramps are common and distressing. The only treatment of proven effectiveness is quinine, but this has a number of side effects. Magnesium salts have been shown to reduce leg cramp distress in pregnancy. This study tests whether magnesium citrate is effective in the treatment of leg cramps in non-pregnant individuals by conducting in a randomised, double-blind, cross-over placebo-controlled trial.
                Volunteers suffering regular leg cramps were recruited. Magnesium citrate equivalent to 300 mg magnesium and matching placebo were given for 6 weeks each. The number of cramps recorded in the cramp diary during the final 4 weeks of magnesium and placebo treatment, severity and duration of cramps and the participants' subjective assessment of effectiveness were analysed.
                In subjects who started with placebo (n=29) the median (95% CI) number of cramps was 9 (6-17) on placebo and 5 (4-8) on magnesium. For the group starting with magnesium (n=17) the median no of cramps was 9 (5-13) on magnesium and 8 (4-14) on placebo. There was no significant carry-over effect (p=0.88), but a highly significant period effect (p=0.008). There was a trend towards less cramps on magnesium (p=0.07). There was no difference in cramp severity and duration between the groups. Significantly more subjects thought that the treatment had helped after magnesium than after placebo 36 (78%) and 25 (54%) respectively, (p=0.03). Diarrhoea was recorded as a side effect of magnesium.
                The results suggest that magnesium may be effective in treatment of nocturnal leg cramps. Further evaluation is recommended. Our purpose was to determine whether women with pregnancy-related leg cramps would benefit from oral magnesium supplementation.
                Seventy-three women with pregnancy-related leg cramps were interviewed about their symptoms in a prospective, double-blind, randomized trial. Initial serum magnesium levels and diurnal magnesium excretion was determined in 50% of the patients. Oral magnesium or placebo was given for 3 weeks, after which new interviews and laboratory analyses were performed.
                Serum magnesium levels in these patients were at or below the lower reference limit, as is also often the case in healthy pregnant patients. Oral magnesium substitution decreased leg cramp distress (p < 0.05 compared with the placebo group, p < 0.001 compared with initial complaints), but did not significantly increase serum magnesium levels, excess magnesium being excreted as measured by an increase in urinary magnesium levels (p < 0.002).
                Oral magnesium supplementation seems to be a valuable therapeutic tool in the treatment of pregnancy-related leg cramps. Rest cramps (also known as nocturnal leg cramps) are very common in a geriatric population. Oral magnesium supplements are marketed for prophylaxis of such cramps but clinical trials exploring the efficacy of oral magnesium conflict. A therapeutic trial of intravenous magnesium overcomes the limited oral bioavailability of magnesium and better assesses its therapeutic potential.
                A double blind, placebo controlled randomized controlled trial was conducted on 46 community-dwelling older adult (69.3 ± 7.7 years) rest cramp sufferers to determine whether 5 consecutive days infusion of 20-mmol (5 g) magnesium sulfate would reduce the frequency of leg cramps per week in the 30 days immediately pre and post infusions. It was also determined whether the response to treatment varied with the extent to which infused magnesium was retained (as measured by 24-hour urinary magnesium excretion).
                The study population averaged 8.0 cramps per week at baseline. The mean change in number of cramps per week, magnesium versus placebo arms, was -2.4 versus -1.7, p = .51, 95% confidence interval of the difference -3.1 to 1.7. Magnesium retention did not correlate with treatment response.
                Intravenous magnesium infusion did not reduce the frequency of leg cramps in a group of older adult rest cramp sufferers regardless of the extent to which infused magnesium was retained. Although oral magnesium is widely marketed to older adults for the prophylaxis of leg cramps, our data suggest that magnesium therapy is not indicated for the treatment of rest cramps in a geriatric population. Our aim was to assess the effect of 360mg magnesium oral substitution daily among pregnant women suffering from leg cramps in pregnancy, defined as painful cramps different from restless legs symptoms.
                In a double blind randomised controlled trial healthy pregnant women between 18 and 36 weeks of pregnancy suffering from painful leg cramps, at least twice a week, were invited to participate. Forty-five women were enrolled initially, 38 completed the treatment and were treated during 2 weeks with either magnesium (360mg=15mmol magnesium lactate and magnesium citrate, Nycoplus Magnesium), or placebo tablets. Serum magnesium and calcium were investigated together with urine magnesium and magnesium-creatinin ratio on day 1 and day 15. Frequency and intensity of leg cramps were recorded. The study was powered to detect a 50% reduction in leg cramps.
                Registration of pain frequency and intensity during the two study weeks demonstrated no significant differences between the two groups. Mean number and intensity of cramps were 9.5 (S.D. 5.1) and 13.2 (S.D. 6.5) in the magnesium group, compared to 7.7 (S.D. 4.7) and 11.4 (S.D. 8.5) in the placebo group. Baseline magnesium levels were 0.77 and 0.74mmol/L in the magnesium group and the placebo group, respectively No significant differences between the two groups, or within the groups, were found when comparing serum values of serum magnesium and total calcium at inclusion time and at the end of the treatment. There was a statistically significant increase in magnesium excretion in the magnesium treatment group (p<0.01). The number of dropouts was two in the treatment group and five in the control group.
                No significant effect on frequency or intensity of leg cramps in pregnant women of magnesium treatment with 360mg daily could be detected in this trial.
It is unlikely that magnesium supplementation provides clinically meaningful cramp prophylaxis to older adults experiencing skeletal muscle cramps. In contrast, for those experiencing pregnancy-associated rest cramps the literature is conflicting and further research in this patient population is needed. We found no randomized controlled trials evaluating magnesium for exercise-associated muscle cramps or disease state-associated muscle cramps (for example amyotrophic lateral sclerosis/motor neuron disease).