Protective effect of magnesium preloading on cisplatin-induced nephrotoxicity: which dose is more suitable?

Cisplatin is a widely used and potent cytotoxic chemotherapy agent, but its nephrotoxicity is a significant limiting side effect. Various premedication approaches have been implemented to preserve renal function, including magnesium (Mg) preloading. However, the optimal Mg dosage is still unknown. Our study aimed to assess the protective effects of different Mg doses as premedication in cisplatin-based chemoradiotherapy for patients with local/locally advanced cervical and head-neck cancers.

This retrospective, multicenter study involved premedication with saline infusion containing potassium chloride and magnesium sulfate (MgSO4) for all patients before cisplatin treatment. Patients were divided into two groups: 12 mEq MgSO4 (low-dose Mg preload group, low-Mg) and 24 mEq MgSO4 (high-dose Mg preload group, high-Mg). Renal function was evaluated using serum creatinine (sCr, mg/dl) and estimated glomerular filtration rate (eGFR, ml/min). Acute kidney injury (AKI) was defined per the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Renal outcomes and efficacy were compared between the groups.

In the low-Mg group (n = 159), sCr levels were significantly higher compared to baseline, various weeks during treatment, and at the 1st, 3rd, 6th, and 12th months post-treatment (p < 0.001). In the high-Mg group (n = 128), no significant changes were observed during treatment and at 1st, 3rd, and 12th months post-treatment (p > 0.05). A significant reduction in mean sCr level from baseline to 6 months was noted in the high-Mg group (p < 0.001). eGFR values are generally correlated with sCr levels. AKI occurred in 21 (13.2%) and 22 (17.7%) patients in the low-Mg and high-Mg groups, respectively (p = 0.292). There was no difference in progression-free or overall survival between the groups.

We clearly demonstrated that saline hydration with 24 mEql MgSO4 supplementation before cisplatin treatment has a better renal protective effect than 12 mEql MgSO4 without reducing efficacy, especially in patients with local/local advanced cervical and head-neck cancer receiving cisplatin with concurrent radiotherapy.