Cockcroft-Gault Creatinine Clearance
Estimate creatinine clearance for renal drug dose adjustment. The FDA and CDSCO standard for pharmacology dosing in adults.
Renal dosing checks baked into the e-Rx
EasyClinic auto-pulls the latest creatinine, computes CrCl, and warns you about metformin, DOACs, aminoglycosides and other renally-cleared drugs — before the patient walks out.
Also Known As
Why Cockcroft-Gault and not eGFR?
For drug dosing, Cockcroft-Gault remains the FDA and CDSCO standard. Most package inserts (vancomycin, gentamicin, DOACs, gabapentin, metformin) specify dose adjustments by Cockcroft-Gault CrCl, not CKD-EPI eGFR. The two are not interchangeable — switching can produce dose errors of 10-30% in elderly and underweight patients.
Use CKD-EPI eGFR for CKD staging and screening. Use Cockcroft-Gault for renally-cleared drug doses.
Common drugs requiring CrCl-based adjustment
- Metformin: Stop if CrCl <30, reduce dose if 30-45
- Apixaban (Eliquis): 2.5 mg BD if 2 of: age ≥80, weight ≤60 kg, Cr ≥1.5
- Rivaroxaban (Xarelto): Avoid if CrCl <15; reduce in AF if 15-49
- Dabigatran: Avoid if CrCl <30
- Enoxaparin: 1 mg/kg OD (instead of BD) if CrCl <30
- Gabapentin, pregabalin: Reduce starting CrCl <60
- Gentamicin, amikacin: Extended interval dosing per CrCl
- Vancomycin: Loading + maintenance dose per CrCl
When Cockcroft-Gault is unreliable
- Acute kidney injury (creatinine has not equilibrated)
- BMI >35 — use adjusted body weight: IBW + 0.4 × (ABW - IBW)
- BMI <18 or muscle wasting (cirrhosis, sarcopenia) — overestimates CrCl
- Amputees, paraplegics — reduced muscle mass
- Pregnancy — GFR rises 50% in 2nd trimester
Frequently Asked Questions
▸Which weight do I use — actual, ideal, or adjusted?
For normal BMI patients, use actual body weight. For BMI >30, use adjusted body weight: IBW + 0.4 × (ABW − IBW). For underweight (BMI <18.5) or muscle-wasted patients, the formula overestimates clearance; consider measured 24-hour urine creatinine clearance.
▸Do I need to multiply by 0.85 for women?
Yes — the original Cockcroft-Gault formula assumes male muscle mass. Women have ~15% less muscle, so multiply by 0.85. Some labs use 0.9 — both are acceptable.
▸What about the difference with eGFR (CKD-EPI)?
CKD-EPI is BSA-normalised (mL/min/1.73m²) and uses different coefficients. For drug dosing, de-normalise CKD-EPI to mL/min by multiplying by BSA/1.73 — but Cockcroft-Gault is still what most drug labels reference, so we recommend using it directly.
▸My patient has serum creatinine 0.5 mg/dL — is the answer realistic?
Low creatinine in a frail elderly patient often reflects reduced muscle mass, not great kidney function. Cockcroft-Gault will give an artificially high CrCl. Many clinicians round up serum creatinine to 1.0 mg/dL in such patients to avoid dosing errors — but this is controversial. Better: measured 24h urine CrCl or use cystatin C.
References
- Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976;16(1):31-41
- FDA Guidance for Industry: Pharmacokinetics in Patients with Impaired Renal Function (2020)
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD
- Indian Society of Nephrology — CKD Practice Guidelines
Auto-adjust renal doses on every prescription
EasyClinic calculates CrCl from the latest creatinine, then flags drugs requiring renal dose adjustment before you sign the prescription.
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