In patients with CrCl less than 50 mL/min, what adjustment is recommended for cimetidine?

• A. Stop therapy
• B. Reduce dose
• C. Increase dose
• D. No adjustment

Answer: (B)

In renal dosing, when kidney function drops, drugs that are cleared by the kidneys can accumulate if the dose isn’t adjusted. Cimetidine is partly eliminated by the kidneys, so with a CrCl under 50 mL/min, the drug stays in the body longer and exposure increases. To prevent this buildup and potential adverse effects, the dose should be reduced (or the dosing interval extended). Stopping the drug isn’t necessary unless there are specific concerns, and increasing the dose would worsen accumulation. So, reducing the dose is the appropriate adjustment.