Magnesium (Mg) Retention and Mood Effects After Intravenous Mg Infusion in Premenstrual Dysphoric Disorder

Background Conflicting data exist regarding the presence of magnesium (Mg) deficiency and the therapeutic efficacy of Mg in premenstrual syndrome or premenstrual dysphoric disorder (PMDD). Methods The % Mg retention was determined using 24-hour urinary Mg excretion and the total dose of Mg given intravenously. In women with (n = 17) and without (n = 14) prospectively diagnosed PMDD, several blood measures of Mg and mood were obtained before, immediately after, and the day following an intravenous Mg (.1 mmol/kg) loading dose. A positive mood response was seen under open conditions; as open Mg infusion improved mood, subsequent PMDD patients (n = 10) were randomized in a double-blind, placebo-controlled, crossover fashion. Results Patients (31.5%) and control subjects (27.5%) retained comparable mean percentages of Mg. Neither group differed in measures of mean Mg before, immediately after, or the day following Mg infusion. Although there was a time effect for all mood measures in the patient group (p<.01 for all), there was neither a treatment nor time-by-treatment effect. Conclusions Contrary to prior reports, we found no evidence of Mg deficiency in women with PMDD compared with control subjects. Furthermore, Mg was not superior to placebo in the mitigation of mood symptoms in women with PMDD.