Metformin: What It Is, Uses, Dosage, and Side Effects

Updated at 2025-05-25

Metformin is a medication used to treat type 2 diabetes. It works by helping to control blood sugar levels, improving the body's sensitivity to insulin, and reducing the amount of sugar produced by the liver. Metformin is commonly prescribed along with diet and exercise to help manage diabetes. (Learn more on DoseMed)

Indications and Uses

Metformin is indicated for:

  • Type 2 Diabetes Mellitus: For the treatment of type 2 diabetes to improve glycemic control.
  • Polycystic Ovary Syndrome (PCOS): Metformin is sometimes used to manage symptoms of PCOS, particularly in women with insulin resistance.

Dosage and Administration

The dosage of Metformin depends on the patient's blood sugar levels and the desired effect:

  • Adults: The usual starting dose is 500 mg once or twice daily, with meals. The dose can be adjusted based on the patient's response.
  • Pediatric Patients (ages 10 and older): The starting dose is typically 500 mg once daily with food, which can be gradually increased.

Contraindications

Metformin is contraindicated in patients with:

  • Severe renal impairment (e.g., creatinine clearance < 30 mL/min).
  • Acute or chronic metabolic acidosis, including diabetic ketoacidosis.

Warnings and Precautions

Serious side effects of Metformin can include lactic acidosis, which is a rare but potentially fatal condition. Patients should be monitored for:

  • Liver Function: Liver function should be monitored regularly, as Metformin can affect liver enzymes.
  • Kidney Function: Kidney function should be evaluated before initiating therapy and periodically thereafter.

Adverse Reactions

Common adverse reactions (≥1%) include:

  • Diarrhea
  • Nausea and vomiting
  • Abdominal pain

Drug Interactions

Notable drug interactions with Metformin include:

  • Cationic Drugs: Drugs like cimetidine and digoxin may affect Metformin levels in the body.
  • Insulin: Careful monitoring of blood glucose levels is required when using Metformin with insulin.

Patient Counseling Information

Patients should be advised to:

  • Take Metformin with food to reduce the risk of gastrointestinal side effects.
  • Report any symptoms of lactic acidosis, such as unusual muscle pain or weakness, difficulty breathing, or stomach discomfort.

Conclusion

Metformin is an effective medication for managing type 2 diabetes and improving glycemic control. Patients should be aware of potential side effects and follow their healthcare provider's instructions for safe use.

For more detailed information, please refer to the official drug label on DailyMed

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