Renal & Fluids
Renal function drives dose adjustment for a large number of drugs, which makes creatinine clearance one of the most consequential numbers in pharmacy. This group covers Cockcroft–Gault — the equation most product labelling is written around, and not the same quantity as a laboratory-reported eGFR — alongside maintenance fluid requirements, infusion rate and drop factor conversions, and the BUN to creatinine ratio. Each states where the estimate stops being reliable: unstable renal function, extremes of body habitus, and low muscle mass.
Creatinine clearance (Cockcroft–Gault) High-risk
Estimate creatinine clearance from age, sex, serum creatinine, and weight — the equation on which most renal dose adjustments in product labelling are based.
Maintenance fluid requirements
Estimate daily maintenance fluid requirements by the Holliday–Segar method, the >20 kg shorthand, and the adult 30–40 mL/kg/day range.
Infusion rate & drop factor
Convert between infusion rate in mL/hr, drops per minute, and total infusion time.
BUN : creatinine ratio
Calculate the ratio of blood urea nitrogen to serum creatinine, a supportive indicator of volume status and the pattern of renal impairment.
High-consequence calculations in this group
These carry a greater risk of harm if the result is wrong or misapplied. Each states its own limits on its page; read them before acting on a number.
- Creatinine clearance (Cockcroft–Gault) — Estimate creatinine clearance from age, sex, serum creatinine, and weight — the equation on which most renal dose adjustments in product labelling are based.
Where to go next
- Practice problems — one worked problem for every calculator, solutions hidden until you open them.
- Reference tables and formula sheet — every constant and conversion factor used here, with citations.
- All 58 calculators — the full index, filterable by category.
Other categories
Also known as
CrCl · creatinine clearance · cockcroft · gault · renal function · kidney function · renal dosing · GFR · maintenance fluid · holliday segar · 4-2-1 · fluid requirement · hydration · mL/kg/day · drip rate · drops per minute · gtt/min · flow rate · infusion · drop factor · IV rate · BUN SCr · BUN creatinine ratio · dehydration · prerenal · volume depletion · azotaemia