Sodium load of novel antibiotics: considerations for nephrologists and clinicians

Background Sodium restriction is a cornerstone in managing patients with chronic kidney disease. Parenteral antibiotic therapy may constitute a hidden and iatrogenic source of sodium overload, particularly relevant in hospitalized and volume-sensitive patient populations. Methods We conducted a structured review of the sodium content of novel antibiotics in nephrology, based on approved Summary of Product Characteristics (SmPC). Standard dosing regimens were used to estimate daily sodium burden in adult patients. Clinical implications were contextualized for patients with chronic kidney disease with or without dialysis. Results Substantial variability in sodium content exists across novel antibiotics. High sodium content of > 3 g/day at standard dosages must be considered with fosfomycin and meropenem/vaborbactam. A sodium load of 1.5 g/day up to 3 g/day is associated with therapy with ceftolozane/tazobactam, cefiderocol, delafloxacin, imipenem/cilastatin/relebactam, and ceftazidime /avibactam at standard dosages utilizing sodium chloride as diluent. For the latter antibiotics, the alternative use of dextrose solutions as diluent reduces significantly the sodium load to values below 1.5 g/day. Eravacycline, lefamulin, ceftaroline fosamil, tedizolid, dalbavancin, and oritavancin itself contain an insignificant amount of sodium; only the diluent, such as sodium chloride, sodium citrate buffer, or Ringer lactate, contributes to a daily sodium load of less than 2 g/day. Conclusion Parenteral antibiotics are an often-overlooked contributor to sodium intake. Clinicians should be aware of this hidden source in sodium-sensitive patients such as kidney disease patients. We propose a visual chart to support sodium-conscious antimicrobial selection as part of broader stewardship strategies.