The effect of magnesium infusion on rest cramps: randomized controlled trial. The effect of oral magnesium substitution on pregnancy-induced leg cramps. Does oral magnesium substitution relieve pregnancy-induced leg cramps? Randomised, cross-over, placebo controlled trial of magnesium citrate in the treatment of chronic persistent leg cramps. Calcium and magnesium status in pregnant women. A comparison between treatment with calcium and vitamin C in pregnant women with leg cramps. Magnesium for the treatment of nocturnal leg cramps: a crossover randomized trial. Magnesium administration and dysrhythmias after cardiac surgery. A placebo-controlled, double-blind, randomized trial. Oral magnesium supplementation improves metabolic variables and muscle strength in alcoholics. A randomized study of intravenous magnesium in acute myocardial infarction treated with direct coronary angioplasty.
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 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. 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. 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. 60 pregnant women underwent a double blind trial with calcium or ascorbic acid (1 g twice daily) as treatment for leg cramps. There was no significant difference between the two treatment groups with respect to clinical improvement. In 14 out of 60 patients the symptoms were totally abolished and in another 27 patients the symptoms were significantly decreased by the treatment (irrespective of drug used). In 17 patients the symptoms were unaffected while only two patients experienced an increase in frequency of their leg cramps during therapy. Serum total and ionized calcium concentrations, serum total magnesium and albumin concentrations were determined and were not significantly changed throughout therapy in any of the groups. No biochemical differences were found between the different treatment regimens or between those patients relieved or not relieved of their symptoms. Serum magnesium concentrations were at or just below the lower normal limit (for non pregnant women) in treated women and pregnant controls. 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. To determine whether magnesium administration is effective in reducing postoperative morbidity and mortality after cardiac surgery.
                Randomized, double-blind, placebo-controlled trial.
                A tertiary acute-care 500-bed university teaching hospital.
                Over a 6-month period, 100 patients electively scheduled for cardiac surgery involving cardiopulmonary bypass were studied.
                Fifty patients were randomized to receive an intravenous infusion of magnesium chloride, 2 g, and 50 patients received placebo intraoperatively after the termination of cardiopulmonary bypass.
                Magnesium-treated patients had a significantly decreased frequency (P < .04) of postoperative ventricular dysrhythmias (eight [16%] of 50) compared with placebo-treated patients (17 [34%] of 50). Patients who were normomagnesemic postoperatively had new supraventricular dysrhythmias less frequently (P < .03) than patients who were hypomagnesemic postoperatively (eight [17%] of 48 vs 19 [37%] of 52). Compared with placebo-treated patients, magnesium-treated patients had significantly higher (P < .02) postoperative cardiac indices in the intensive care unit (2.8 +/- 0.1 vs 2.5 +/- 0.1 L/min per m2). Patients with postoperative total and ultrafilterable hypomagnesemia had postoperative ventricular dysrhythmias (P < .04) and required prolonged mechanical ventilatory support (P < .01) more frequently than patients without postoperative hypomagnesemia.
                Total and ultrafilterable hypomagnesemia are prevalent findings in cardiac surgery patients, and postoperative hypomagnesemia is strongly associated with clinically important morbidity. Magnesium administration decreased the frequency of postoperative ventricular dysrhythmias and increased the stroke volume and thereby cardiac index in the early postoperative period. Magnesium deficiency is common among chronic alcoholics, but the knowledge of oral magnesium supplementation to this group is limited. We, therefore, randomized 49 chronic alcoholics, moderate to heavy drinkers for at least 10 years to receive oral magnesium or placebo treatment for 6 weeks according to a double-blind protocol. Effects on metabolic variables and muscle strength were analyzed. Significant reduction of aspartate-aminotransferase (ASAT), alanine-aminotransferase (ALAT) and gamma-glutamyl-transpeptidase (GGT) were seen after magnesium, whereas no change was observed with placebo. Bilirubin decreased in both groups. Serum Na, Ca, and P increased significantly during magnesium therapy compared with no statistically significant change in the placebo group. Serum K and Mg increased slightly after magnesium supplementation and decreased in the placebo group, resulting in a significant difference between the two groups at the end of the study. Muscle strength increased significantly during magnesium treatment, contrasting to no change with placebo. Blood pressure, heart rate, hematological variables, serum lipids (cholesterol, HDL, TG), glucose tolerance, and creatinine were unchanged in the two groups after treatment. Alcohol consumption was similar before and during the trial and does not explain the differences between the two groups The results shows that short-term oral magnesium therapy may improve liver cell function, electrolyte status, and muscle strength in chronic alcoholics. Notwithstanding the negative result of the International Study of Infarct Survival-4 (ISIS-4), the controversy about the role of magnesium in acute myocardial infarction is still open because, according to experimental data, magnesium could decrease myocardial damage and mortality only if infusion is started before reperfusion. This randomized placebo-controlled trial was designed to evaluate the effect of intravenous magnesium, delivered before, during, and after direct coronary angioplasty, in patients with acute myocardial infarction.
                One-hundred fifty patients were randomized to intravenous magnesium sulfate or placebo. The primary end point was an infarct zone wall motion score index at 30 days, as a measure of infarct size. The secondary end points included creatine kinase peak, ventricular fibrillation/tachycardia within the first 24 hours, death and congestive heart failure within the 30-day follow-up, and 30-day left ventricular ejection fraction. Analysis was by intention to treat.
                There were no significant differences between the magnesium and placebo groups in the 30-day infarct zone wall motion score index (1.93 +/- 0.61 vs 1.85 +/- 0.51, P =.39), ventricular arrhythmias (24% vs 15%, P =.15), death (0 vs 1%, P =.32), heart failure (8% vs 7%, P =.75), and 30-day left ventricular ejection fraction (49% +/- 11% vs 50% +/- 9%, P = 0.55). There was a trend toward a higher creatine kinase peak in the magnesium group (3059 +/- 2359 vs 2404 +/- 1673,P =.052).
                Intravenous magnesium delivered before, during, and after reperfusion did not decrease myocardial damage and did not improve the short-term clinical outcome in patients with acute myocardial infarction treated with direct angioplasty.
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).