Which drug requires a dose reduction when CrCl is <30 mL/min?

• A. Enoxaparin
• B. Fondaparinux
• C. Naproxen
• D. Nifedipine

Answer: (A)

In older adults, any drug that is cleared by the kidneys can build up when kidney function is very low, increasing the risk of toxicity and adverse effects. Enoxaparin is a low molecular weight heparin that is primarily cleared renally, so when CrCl falls below 30 mL/min, a dose reduction is advised to avoid excessive anticoagulation and bleeding. Fondaparinux, while also renally cleared, is generally avoided or contraindicated at CrCl <30 due to a high bleeding risk, rather than simply reduced dosing. Naproxen is an NSAID with risks in chronic kidney disease and is typically avoided or used with great caution rather than having a standard dose-reduction rule tied specifically to CrCl <30. Nifedipine does not require dose adjustment for this level of renal impairment. Therefore, the drug that specifically requires a dose reduction when CrCl is below 30 is enoxaparin.