👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Pharmacological Therapies🔖 Free to read, print, and share
Also known as: Glucophage · diabetes pill · biguanide
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Use this quick-reference guide to spot, treat, and prevent Metformin on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
✅ Action
Biguanide, ↓hepatic glucose
Doesn't cause hypoglycemia alone
📌 Hold
Hold 48h around contrast dye
Renal risk → lactic acidosis
🚩 Report
Lactic acidosis: muscle pain, weak
Malaise, ↑RR, drowsiness
🎓 Teach
Take with food → ↓GI upset
Limit alcohol, monitor renal
📚 Metformin — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
Metformin is a biguanide oral antidiabetic and the first-line drug for type 2 diabetes. It lowers glucose by decreasing hepatic glucose production and improving insulin sensitivity without causing hypoglycemia on its own. Key principle: hold it around iodinated contrast studies because of the risk of lactic acidosis.
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Key points
Understand these first
Metformin does not cause hypoglycemia when used alone because it does not increase insulin secretion.
It must be held for 48 hours before and after IV iodinated contrast to prevent lactic acidosis.
It is contraindicated in renal impairment, which raises lactic acidosis risk.
Common GI side effects include nausea, diarrhea, and metallic taste, often improving over time.
Long-term use can cause vitamin B12 deficiency.
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Nursing priorities
What to do, in order
Verify renal function (creatinine, eGFR) before and during therapy.
Hold the drug before contrast procedures and confirm renal function before restarting.
Monitor blood glucose and A1C for therapeutic response.
Assess for signs of lactic acidosis: muscle pain, weakness, fatigue, and trouble breathing.
Never give within 48 hours of IV contrast without renal clearance.
Report worsening kidney function.
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Labs & values
Numbers to know
Fasting glucose 70-99 mg/dL
Hemoglobin A1C below 7% (goal for most diabetics)
Creatinine 0.6-1.2 mg/dL
Lactate 0.5-2.2 mmol/L
Vitamin B12 200-900 pg/mL
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Patient teaching
What patients must know
Take with food to limit nausea and diarrhea.
Avoid excessive alcohol, which increases lactic acidosis risk.
Continue diet and exercise; it controls but does not cure diabetes.
❓ Metformin: NCLEX FAQs
What are the priority nursing interventions for Metformin?
Verify renal function (creatinine, eGFR) before and during therapy. Hold the drug before contrast procedures and confirm renal function before restarting. Monitor blood glucose and A1C for therapeutic response. Assess for signs of lactic acidosis: muscle pain, weakness, fatigue, and trouble breathing.
What are the warning signs of Metformin a nurse must report?
Report muscle pain, unusual fatigue, hyperventilation, or abdominal distress (lactic acidosis). Never give within 48 hours of IV contrast without renal clearance. Report worsening kidney function.
What do I need to know about Metformin for the NCLEX?
Metformin does not cause hypoglycemia when used alone because it does not increase insulin secretion. It must be held for 48 hours before and after IV iodinated contrast to prevent lactic acidosis. It is contraindicated in renal impairment, which raises lactic acidosis risk. Common GI side effects include nausea, diarrhea, and metallic taste, often improving over time.
What patient teaching is important for Metformin?
Take with food to limit nausea and diarrhea. Avoid excessive alcohol, which increases lactic acidosis risk. Continue diet and exercise; it controls but does not cure diabetes.
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Quick Tip
Metformin does not cause hypoglycemia when used alone because it does not increase insulin secretion.