Background Hypomagnesaemia is a well-known side effect of cisplatin, induced by the drug’s renal toxicity. Although hypomagnesaemia refers to any magnesium level below 1.7 mg/dL, it does not lead to clinical symptoms until levels <1.2 mg/dL. Life-threatening consequences have been reported only when levels <0.7 mg/dL.

Purpose To evaluate the incidence and severity of cisplatin-induced hypomagnesaemia.

Material and methods A retrospective and observational study (April 2001–March 2014) was conducted in a General Hospital (600 beds). All patients who had received at least one dose of cisplatin were included. Start date of cisplatin chemotherapy, gender, age, tumour type and blood magnesium levels were collected for each patient. According to the hospital protocol, patients receive magnesium supplementation before and after cisplatin and aggressive hydration in order to prevent nephrotoxicity.

All patients with hypomagnesaemia were classified according to the CTCAE grade.

Results 528 patients (3,682 cisplatin administrations) were included (79.3% male, mean age = 56.68 ± 12.29 years).

Magnesium level was assessed in 6,021 blood tests and it was below the lower limit in 1,421 of them. Hypomagnesaemia was observed in at least one blood test, in 320 patients (60.6%), during or after treatment.

The incidence of hypomagnesaemia was similar for men and women (60.3% vs. 61.7%).

93.9% of patients with haematological malignancies and 57.2% of patients with solid tumours showed hypomagnesaemia in at least one blood test, (OR: 11.47; IC95%: 3.52–37.40; p < 0.05).

Mean time until onset of hypomagnesaemia was 211 days and in the vast majority of patients (89.4%) this happened within the first year of treatment.

Conclusion

• Hypomagnesaemia is a common and long-term side effect of cisplatin but only in very few cases was it considered to be severe. The incidence of life-threatening hypomagnesaemia is extremely low.

• The prevalence of hypomagnesaemia was much higher in haematological patients than in patients with solid tumours.

Reference

1. Pham PC, Pham PA, Pham SV, et al. Hypomagnesemia: a clinical perspective. Int J Nephrol Renovasc Dis 2014;7:219–30

ReferenceNo conflict of interest.