Significant renal impairment — dose-adjustment engine

When renal function is significantly reduced (roughly eGFR/CrCl <30 or dialysis — though some drugs need adjustment earlier), dental drug safety problems come from: (1) drug accumulation causing toxicity, (2) drug removal by hemodialysis causing underdosing if not timed, and (3) nephrotoxic drugs causing AKI or further decline. This card is the APP DOSE-ADJUSTMENT ENGINE: estimate renal function, THEN consult each drug's own product label. Do not treat eGFR (CKD-EPI), CKD stage, and creatinine clearance (Cockcroft-Gault) as interchangeable — each label states which estimate and cut-offs to use, and thresholds differ by drug (e.g. cephalexin is already capped at 1 g/day in the CrCl 30-59 band, above the old '<30' trigger). It stores per-drug renal adjustment rules, HD timing logic, and NSAID caution as the core prescribing safety layer for all renal conditions.