Background and Importance Magnesium deficiency is mainly manifested in cardiac and neuromuscular disorders. Hypomagnesaemia has been described as a frequent adverse reaction associated with the intravenous administration of liposomal amphotericin B.

Aim and Objectives To compare associated hypomagnesaemia in patients with fungal infection receiving standard- versus high-dose of liposomal amphotericin B.

Material and Methods One-year retrospective observational study including patients who received liposomal amphotericin B for at least 5 days. The variables collected were age, sex, mean dose, duration of treatment, serum magnesium and need for magnesium supplementation. Patients were divided into two groups: standard doses (≤ 3 mg/kg/day) and high doses (> 3 mg/kg/day). The change in magnesium at the beginning and the end of the period studied in each of the groups was analysed.

Results A total of 31 patients (38% women) with a mean age of 60±13 years were included. The baseline magnesium value of the patients who started treatment was 1.95±0.34 mg/dl, with only two patients being below the physiological range (1.6–2.4 mg/dl).

In the standard dose group, 11 patients (35%) were included with a mean dose of 1.63±0.84 mg/kg/day and a mean duration of 22±10 days. At five days, no patient was below the physiological range, although magnesium decreased by an average of 0.076 mg/dl (4% with respect to baseline). This meant that 45% of the patients had to be supplemented with intravenous magnesium. In the high-dose group, 20 patients (64%) were included, who received a mean dose of 4.88±0.91 mg/kg/day for a mean of 17±10 days. On the fifth day, 20% of the patients showed levels below the physiological range of magnesium. Furthermore, the mean decrease in this group was 0.195 mg/dl (10%), with 65% requiring exogenous supplementation. There are statistically significant differences (p<0.05) showing that a greater decrease in serum magnesium levels is associated with high-dose amphotericin.

Conclusion and Relevance Real-life data show a greater decrease in serum magnesium with high doses of liposomal amphotericin B. Therefore, monitoring and follow-up of these patients -who will require more frequent magnesium supplementation- is a priority.

Conflict of Interest No conflict of interest.