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Magnezij za grčeve u mišićima

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Abstract

Background

Skeletal muscle cramps are common and often presented to physicians in association with pregnancy, advanced age, exercise or disorders of the motor neuron (such as amyotrophic lateral sclerosis). Magnesium supplements are marketed for the prophylaxis of cramps but the efficacy of magnesium for this indication has never been evaluated by systematic review.

Objectives

To assess the effects of magnesium supplementation compared to no treatment, placebo control or other cramp therapies in people with skeletal muscle cramps.  

Search methods

We searched the Cochrane Neuromuscular Disease Group Specialized Register (11 October 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (2011, Issue 3), MEDLINE (January 1966 to September 2011), EMBASE (January 1980 to September 2011), LILACS (January 1982 to September 2011), CINAHL Plus (January 1937 to September 2011), AMED (January 1985 to October 2011) and SPORTDiscus (January 1975 to September 2011).

Selection criteria

Randomized controlled trials (RCTs) of magnesium supplementation (in any form) to prevent skeletal muscle cramps in any patient group (i.e. all clinical presentations of cramp). We considered comparisons of magnesium with no treatment, placebo control, or other therapy.

Data collection and analysis

Two authors independently selected trials for inclusion and extracted data. Two authors assessed risk of bias. We attempted to contact all study authors and obtained patient level data for three of the included trials, one of which was unpublished. All data on adverse effects were collected from the included RCTs.

Main results

We identified seven trials (five parallel, two cross‐over) enrolling a total of 406 individuals amongst whom 118 cross‐over participants additionally served as their own controls. Three trials enrolled women with pregnancy‐associated leg cramps (N = 202) and four trials enrolled idiopathic cramp sufferers (N = 322 including cross‐over controls). Magnesium was compared to placebo in six trials and to no treatment in one trial.

For idiopathic cramps (largely older adults presumed to have nocturnal leg cramps), differences in measures of cramp frequency, magnesium versus placebo, were small, not statistically significant, and without heterogeneity (I2 = 0%). This includes the primary endpoint, percentage change from baseline in the number of cramps per week at four weeks (‐3.93%, 95% confidence interval (CI) ‐21.12% to 13.26%, moderate quality evidence) and the difference in the number of cramps per week at four weeks (0.01 cramps/week, 95% CI ‐0.52 to 0.55, moderate quality evidence). The percentage of individuals experiencing a 25% or better reduction in cramp rate from baseline was also no different, being 8% lower in the magnesium group (95% CI ‐28% to 12%, moderate quality evidence). Similarly, no statistically significant difference was found at four weeks in measures of cramp intensity (moderate quality evidence) or cramp duration (low quality evidence).

Meta‐analysis was not possible for trials of pregnancy‐associated leg cramps. The single study comparing magnesium to no treatment failed to find statistically significant benefit on a three‐point ordinal scale of overall treatment efficacy. The two trials comparing magnesium to placebo differed in that one trial found no benefit on frequency or intensity measures while the other found benefit for both.

Withdrawals due to adverse events were not significantly different than placebo. While we could not determine the number of subjects with minor adverse events, studies of oral magnesium generally described potential side effects as similar in frequency to placebo.

Authors' conclusions

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).

PICO

Population
Intervention
Comparison
Outcome

El uso y la enseñanza del modelo PICO están muy extendidos en el ámbito de la atención sanitaria basada en la evidencia para formular preguntas y estrategias de búsqueda y para caracterizar estudios o metanálisis clínicos. PICO son las siglas en inglés de cuatro posibles componentes de una pregunta de investigación: paciente, población o problema; intervención; comparación; desenlace (outcome).

Para saber más sobre el uso del modelo PICO, puede consultar el Manual Cochrane.

Magnezij za grčeve u mišićima

Grčevi u mišićima često se javljaju i mogu nastupiti u različitim situacijama. Starije odrasle osobe i trudnice se često žale na grčeve u mišićima pri mirovanju, sportaši mogu imati grčeve kada testiraju granice izdržljivosti, dok se kod nekih ljudi oni pojavljuju kao simptom drugih zdravstvenih problema. Mogući način liječenja grčeva, koji se već i reklamira za njihovu prevenciju, jest nadopuna magnezija. Magnezij je uobičajeni mineral u prehrani, a kao dodatak prehrani je dostupan putem interneta ili u prodavaonicama zdrave hrane i ljekarnama (obično u vidu tableta ili prašaka koji se otapaju u vodi). U okviru Cochrane sustavnog pregleda literature tražena su objavljena visoko kvalitetna istraživanjima u kojima se procjenjivao učinak magnezija za sprječavanje mišićnih grčeva te su nađena četiri istraživanja na starijim odraslim osobama te tri istraživanja na trudnicama. Nije bilo istraživanja na ljudima koji grčeve imaju tijekom vježbanja, kao ni na ljudima kod kojih su grčevi uzrokovani zdravstvenim problemima. Rezultati iz četiri istraživanja na odraslim ljudima (s ukupno 322 sudionika uključujući i kontrole u ukriženim studijama) zbirno upućuju na zaključak kako nije vjerojatno da upotreba magnezija ima učinka u smanjivanju učestalosti ili jačine grčeva kod te populacije. Autori procjenjuju da je ovaj dokaz osrednje kvalitete. Tri istraživanja na trudnicama (202 sudionika) zbirno ne upućuju na jasan zaključak. U jednom se istraživanju dodatak magnezija pokazao koristan za smanjenje učestalosti i bolnosti grčeva, dok u druga dva nije. Potrebne su dodatne studije o primjeni magnezija kod trudnica. Međutim, čini se da nije vjerojatno da starije odrasle osobe imaju koristi od ovakve terapije. Iako nije bilo moguće odrediti stopu neželjenih nuspojava, stope povlačenja iz studije i rasprave o štetnim učincima upućuju na dobro podnošenje terapije magnezijem.