Which antibiotics are listed as antinfectives to avoid with CrCl <30?

• A. Ciprofloxacin
• B. Nitrofurantoin
• C. Trimethoprim-sulfamethoxazole
• D. All of the above

Answer: (D)

When kidney function is severely reduced (creatinine clearance under 30 mL/min), many drugs that are normally safe can accumulate to toxic levels. The Beers Criteria flags certain antinfectives for avoidance in this scenario because the risks of adverse effects or reduced efficacy outweigh the benefits.

Ciprofloxacin, a fluoroquinolone, is avoided at CrCl <30 because its clearance is markedly decreased and the drug can cause serious CNS effects, QT prolongation, and tendon disorders in older adults, with heightened risk when renal function is impaired. Nitrofurantoin relies on adequate renal function to achieve effective urinary concentrations; with CrCl <30, systemic exposure increases and urinary efficacy diminishes, raising concerns for toxicity and treatment failure. Trimethoprim-sulfamethoxazole can lead to hyperkalemia, hyponatremia, and nephrotoxicity, and these risks are amplified when kidney function is poor, making it safer to avoid in severe renal impairment.

Because each of these antibiotics has safety or efficacy concerns tied to CrCl <30, all of them are listed as antinfectives to avoid in that setting. If treatment is needed, alternative agents or dosing strategies that account for renal function are considered.