Synopsis
Choose the correct kidney-function estimate, individualise medicine exposure and monitor or restart essential treatment safely across CKD, AKI, dialysis and intercurrent illness.
- Start with the medicine's indication and urgency. Dose adjustment that makes an antimicrobial ineffective or permanently removes kidney- and heart-protective treatment can be as harmful as accumulation.
- Decide whether kidney function is stable. Creatinine-based eGFR and Cockcroft–Gault creatinine clearance assume relative steady state and can substantially mislead during rapidly evolving AKI.
- For most medicines in an average-sized stable adult, BNF renal advice commonly uses eGFR, but the exact monograph or Summary of Product Characteristics determines which estimate and threshold apply.
Key red flags
Intercurrent volume loss or sepsis combined with NSAID exposure, renin–angiotensin blockade and diuretic treatment can sharply reduce glomerular perfusion. The physiology and original indications determine which items are paused and restored.
Investigation priorities
Determine whether renal function is stable enough for an estimate and identify the direction and speed of change.
Management branches
A medicine is being started or renewed in a person with known or suspected kidney impairment.
- Confirm indication, urgency, allergy, pregnancy, current and baseline renal trajectory, recent weight, body composition, dialysis status and all interacting or duplicate products.
- Consult the current BNF monograph and SmPC to identify whether eGFR, Cockcroft–Gault clearance or specialist monitoring drives the dose, interval, contraindication and loading strategy.
Key medicines
Direct-acting oral anticoagulantSelect the agent and licensed indication-specific regimen from current BNF and SmPC using Cockcroft–Gault creatinine clearance, age, weight and interacting treatment.
Renin–angiotensin system inhibitorContinue or titrate for the licensed kidney, cardiovascular or blood-pressure indication with creatinine and potassium checks; temporarily withhold during selected dehydrating or hypotensive illness under the care plan.