Question: what gfr should metformin be stopped?
Answer: Do not use metformin among patients with an eGFR less than 30. Do not start metformin among patients with an eGFR between 30 to 45. Stop metformin if a patient's eGFR drops less than at any point during therapy. Complete a risk-benefit analysis of metformin if a patient's eGFR drops to less than 45.