Metformin is contraindicated in males with creatinine level greater than what, and in females greater than what?

Metformin is contraindicated in males with creatinine level greater than what, and in females greater than what?

• A. Creatinine > 2.0 mg/dL in men or >1.8 mg/dL in women
• B. Creatinine > 1.0 mg/dL in men or >0.9 mg/dL in women
• C. Creatinine > 1.5 mg/dL in men or >1.4 mg/dL in women
• D. eGFR <60 mL/min/1.73 m2

Answer: (B)

Metformin safety depends on kidney function because the drug is cleared by the kidneys and can accumulate when renal function is reduced, increasing the risk of lactic acidosis. To protect patients, kidney function thresholds using creatinine levels have been used to decide when metformin should not be started or should be stopped. In this context, metformin is contraindicated when creatinine is greater than 1.0 mg/dL in men or greater than 0.9 mg/dL in women. The reason for the sex difference is that men generally have higher baseline creatinine production due to greater muscle mass, so the same creatinine level represents different degrees of renal impairment between sexes. While modern practice often uses eGFR to guide metformin dosing and contraindications, this creatinine-based threshold is a common way questions test understanding of how renal function affects metformin safety.

Metformin safety depends on kidney function because the drug is cleared by the kidneys and can accumulate when renal function is reduced, increasing the risk of lactic acidosis. To protect patients, kidney function thresholds using creatinine levels have been used to decide when metformin should not be started or should be stopped. In this context, metformin is contraindicated when creatinine is greater than 1.0 mg/dL in men or greater than 0.9 mg/dL in women. The reason for the sex difference is that men generally have higher baseline creatinine production due to greater muscle mass, so the same creatinine level represents different degrees of renal impairment between sexes. While modern practice often uses eGFR to guide metformin dosing and contraindications, this creatinine-based threshold is a common way questions test understanding of how renal function affects metformin safety.