Medication Adjustment for Diabetes with GFR 36
You need to reduce your metformin dose to 500mg twice daily (maximum 1000mg/day total) and continue Farxiga 5mg, while adding a GLP-1 receptor agonist like semaglutide or liraglutide for additional glucose control and cardiovascular protection. 1
Immediate Metformin Dose Adjustment Required
Your current metformin dose of 1000mg twice daily (2000mg/day total) is too high for your kidney function and must be reduced:
- With GFR 30-44 mL/min/1.73m² (stage 3B CKD), metformin should be reduced to a maximum of 1000mg per day total 2, 1, 3
- The recommended dosing schedule is 500mg twice daily (morning and evening) 4
- Metformin should never be initiated at GFR <45 mL/min/1.73m², but since you're already taking it, dose reduction rather than discontinuation is appropriate 2
- Metformin becomes absolutely contraindicated if your GFR drops below 30 mL/min/1.73m² 2, 1, 3
Critical Safety Point
At your current dose, you are at increased risk for lactic acidosis. The FDA revised metformin labeling specifically to address this: benefits and risks must be reassessed when eGFR falls below 45 mL/min/1.73m² 2. Research confirms that 1000mg daily maintains stable, safe blood metformin concentrations in stage 3B CKD without causing hyperlactatemia 4.
Continue Farxiga (Dapagliflozin) 5mg
Your current Farxiga dose is appropriate and should be continued because:
- SGLT2 inhibitors are recommended as first-line therapy for diabetic patients with CKD when eGFR ≥20 mL/min/1.73m² 1
- Dapagliflozin specifically reduces progression of diabetic kidney disease 2
- SGLT2 inhibitors reduce cardiovascular events and heart failure hospitalization risk 2
- Your GFR of 36 is well above the minimum threshold of 20 for SGLT2 inhibitor use 1
Add a GLP-1 Receptor Agonist
You should add a long-acting GLP-1 receptor agonist to your regimen 1:
Preferred Options (in order):
- Semaglutide 0.5-1mg weekly - provides cardiovascular benefits and requires no dose adjustment for kidney function 2, 1
- Liraglutide 1.2-1.8mg daily - reduces cardiovascular events and death risk 2, 1
- Dulaglutide 0.75-1.5mg weekly - reduces cardiovascular events 2, 1
Why Add This Class:
- GLP-1 receptor agonists are recommended for patients with type 2 diabetes and CKD who need additional glucose control beyond metformin and SGLT2 inhibitors 2, 1
- They provide proven cardiovascular disease benefit, which is critical given your kidney disease 2
- No dose adjustment is required for any level of kidney function 1
- They reduce risk of CKD progression and have minimal hypoglycemia risk 2
Important Safety Measures When Making These Changes
Dose Adjustment Protocol:
- When adding the GLP-1 receptor agonist, if you're already meeting glucose targets, any sulfonylurea or insulin doses should be reduced by 25-50% to prevent hypoglycemia 1
- Monitor for volume depletion when using SGLT2 inhibitors, especially with reduced kidney function 1
Monitoring Requirements:
- Check vitamin B12 levels periodically - long-term metformin use causes biochemical B12 deficiency 2
- Your kidney function (eGFR) must be monitored regularly - if it drops below 30, metformin must be stopped entirely 2, 1
- Hypoglycemia risk increases dramatically when eGFR <45 mL/min/1.73m², requiring careful glucose monitoring 1
Contrast Media Precaution:
If you need any imaging study with IV contrast dye, metformin must be stopped the day of the procedure and held for 48 hours afterward since your GFR is <60 mL/min/1.73m² 3
Additional Essential Treatments
Beyond glucose control, you need:
- ACE inhibitor or ARB if you have hypertension and protein in your urine (albuminuria) - target systolic BP to 130 mmHg 1
- Statin therapy is mandatory regardless of your cholesterol levels to reduce cardiovascular risk 1
- Consider continuous glucose monitoring - HbA1c becomes less reliable in advanced CKD 1
What NOT to Use
Avoid these medications with your kidney function: