- Body system
- Endocrine
- Brand names
- Glucophage, Glumetza, Fortamet, Riomet
What is Metformin used for?
- Type 2 diabetes (usually the first-line drug)
How Metformin works
Biguanide: lowers glucose production by the liver and improves the body's response to insulin. Used alone, it rarely causes hypoglycemia.
Common side effects
- Diarrhea, nausea, bloating, metallic taste
- Vitamin B12 deficiency with long-term use
Report right away
- Unusual muscle pain, trouble breathing, stomach pain, extreme tiredness or feeling cold (lactic acidosis)
Nursing considerations for Metformin
- Check kidney function: metformin is contraindicated when the eGFR is below 30 mL/min/1.73 m², and starting it is not recommended between 30 and 45.
- Hold before or at the time of an iodinated contrast study in patients at risk (eGFR 30 to 60, liver disease, alcohol use, heart failure, intra-arterial contrast) and restart only after kidney function is rechecked about 48 hours later, per protocol.
- Usually held before surgery and in acute illness with dehydration or hypoxia.
Patient teaching
- Take with meals to reduce stomach upset; GI effects often fade after a few weeks.
- Limit alcohol.
- Swallow extended-release tablets whole; a tablet shell may appear in the stool and is harmless.
This card does not list doses. Use the prescriber's order, the product label and a current drug reference for dosing, and follow your facility's policies.
Oral and non-insulin antidiabetic drugs practice questions
NCLEX-style questions on the class Metformin belongs to.
3 questions. Choose an answer to see the rationale.
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Which test result should the nurse check before giving metformin to a patient scheduled for a CT scan with IV contrast?
Show answer
Answer A: eGFR or serum creatinine Iodinated contrast can impair kidney function, and metformin builds up in kidney impairment, raising the risk of lactic acidosis.
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Which drug is most likely to cause hypoglycemia when used alone?
Show answer
Answer D: Glipizide Sulfonylureas stimulate insulin release regardless of the glucose level, so hypoglycemia is their main risk.
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A patient taking empagliflozin should be taught to watch for which effect?
Show answer
Answer B: Genital yeast infections SGLT2 inhibitors put glucose into the urine, which raises the risk of genital fungal infections and urinary infections.
Frequently asked questions
What is Metformin used for?
Type 2 diabetes (usually the first-line drug).
What drug class is Metformin?
Metformin belongs to the class oral and non-insulin antidiabetic drugs. Biguanide: lowers glucose production by the liver and improves the body's response to insulin. Used alone, it rarely causes hypoglycemia.
What are the nursing considerations for Metformin?
Check kidney function: metformin is contraindicated when the eGFR is below 30 mL/min/1.73 m², and starting it is not recommended between 30 and 45. Hold before or at the time of an iodinated contrast study in patients at risk (eGFR 30 to 60, liver disease, alcohol use, heart failure, intra-arterial contrast) and restart only after kidney function is rechecked about 48 hours later, per protocol.
What should patients report while taking Metformin?
unusual muscle pain, trouble breathing, stomach pain, extreme tiredness or feeling cold (lactic acidosis).