A Double-Blind Randomized Placebo Controlled Trial of Magnesium Oxide for Alleviation of Chronic Low Back Pain

Abstract

This double-blind randomized placebo controlled trial used a pre-test/post-test control group design. Sixty adults patients complaining of chronic low back pain (greater than six months) were recruited from a free standing major metropolitan pain center. Half of the patients received an oral 800mg magnesium oxide supplement and half received an oral placebo every day for a two-month trial period. Laboratory analysis of serum total magnesium, serum ionized magnesium, and sublingual (tissue) magnesium levels (Exatest, ICD Inc.) were performed before and after the trial. All patients were asked to assess their pain and various quality of life indicators using a 10 point Likert Scale before and after the trial. In the magnesium treated group starting pain scores reported a mean of 6.6 (SD+2.0) and post study pain scores were reported with a mean of 6.4 (SD+1.7).There were no significant changes in pre or post study magnesium levels in the treatment group. Total serum and serum ionized magnesium levels correlated (p<.001), but no significant correlation (p=.828) was noted between total serum and sublingual (tissue) magnesium levels. The average diastolic blood pressure in the magnesium treated group decreased significantly (5.9mmHg; p =.040). Surprisingly, the total serum magnesium levels increased by 0.05mM/L in the placebo group. Although these data do not support the hypothesis that oral magnesium oxide supplementation can reduce chronic pain, compliance was not confirmed, so replication of this study with a more controlled patient population may be beneficial. As magnesium levels did not rise significantly, a higher dose or a more absorbable magnesium chelate might be more effective. A magnesium wasting effect of orally administered magnesium oxide may also need to be considered.