Which method is commonly used to estimate renal function in adults for drug dosing?

• A. MELD score
• B. Child-Pugh score
• C. Cockcroft-Gault or MDRD/eGFR
• D. Cumulative illness rating

Answer: (C)

Estimating renal function is essential for dosing drugs that are cleared by the kidneys. The amount the kidneys can filter affects how quickly a drug is eliminated, so clinicians use equations that translate a patient’s kidney performance into a usable dosing guide. The Cockcroft-Gault equation estimates creatinine clearance from age, weight, sex, and serum creatinine, and has long been used specifically for dosing decisions because its output is in units that mirror drug clearance. The MDRD or CKD-EPI equations estimate glomerular filtration rate, which is another measure of kidney function and is widely used to assess renal status and adjust dosing in many situations. In practice, these methods provide the information needed to tailor doses to avoid drug buildup and toxicity.

In contrast, the MELD and Child-Pugh scores are designed to evaluate liver function and prognosis, not renal clearance, and the Cumulative Illness Rating is a general comorbidity index. Therefore, the methods used to estimate renal function for drug dosing are Cockcroft-Gault or MDRD/eGFR.