In patients with reduced renal function, what is the recommended dosing approach?

• A. Increase dose to achieve therapeutic levels
• B. Reduce dose or extend the dosing interval
• C. No change in dosing
• D. Stop therapy completely

Answer: (B)

When kidney function is reduced, the body's ability to clear drugs that are excreted by the kidneys drops, leading to higher and longer-lasting drug levels in the blood. To prevent accumulation and potential toxicity, the dosing plan should be adjusted. The best approach is to either reduce the amount given with each dose or extend the time between doses (or both). This keeps overall exposure closer to what is seen in people with normal renal function, even though clearance is slower. Dose adjustments are usually guided by creatinine clearance or eGFR and are drug-specific because some medicines have active metabolites or narrow safety margins.

Increasing the dose would worsen accumulation and toxicity; not changing the dose ignores the altered clearance; stopping therapy completely is not typically needed unless there are specific safety concerns.