In the setting of rapidly improving/worsening renal function, calculations of eGFR are inaccurate, and dosing should be based on estimated renal function instead.
If worsening renal function, actual GFR is likely lower than calculated.
If improving renal function, actual GFR is likely higher than calculated eGFR.
500mg PO q24h
500mg PO q8-12h
500-1000mg PO q8h
500-1000mg po q24h - take after dialysis on HD days