What is the recommended dose and frequency of Metformin (Metformin hydrochloride)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Article Review Status
Submitted
Under Review
Approved

Last updated: May 19, 2025 • View editorial policy

From the Guidelines

Metformin should be initiated at a dose of 500 mg once or twice daily with meals, and gradually increased to a maximum dose of 2000 mg daily, with dose adjustments based on kidney function, as recommended by the most recent guidelines 1.

Key Considerations

  • The extended-release formulation can be taken once daily, usually with the evening meal, starting at 500 mg and increasing to 2000 mg daily as tolerated.
  • Taking metformin with food helps reduce stomach upset, nausea, and diarrhea, which are common side effects when initiating therapy.
  • Metformin is contraindicated in patients with significantly impaired kidney function (eGFR <30 mL/min) and dose adjustments are needed for moderate impairment.
  • Regular monitoring of kidney function is important, with eGFR monitored every 3 to 6 months in those at risk for decline in kidney function 1.

Dosing Adjustments

  • For patients with an eGFR ≥60 mL/min/1.73 m², the standard dose can be used.
  • For patients with an eGFR 45-59 mL/min/1.73 m², consider dose reduction in certain conditions.
  • For patients with an eGFR 30-44 mL/min/1.73 m², halve the dose.
  • For patients with an eGFR <30 mL/min/1.73 m², metformin is contraindicated.

Additional Recommendations

  • Monitor patients for vitamin B12 deficiency when they are treated with metformin for more than 4 years 2.
  • Metformin may be temporarily discontinued before procedures including imaging studies using iodinated contrast, during hospitalizations, and when acute illness may compromise renal or liver function 1.

From the FDA Drug Label

The recommended starting dose of metformin hydrochloride tablets are 500 mg orally twice a day or 850 mg once a day, given with meals. Increase the dose in increments of 500 mg weekly or 850 mg every 2 weeks on the basis of glycemic control and tolerability, up to a maximum dose of 2550 mg per day, given in divided doses.

Doses above 2000 mg may be better tolerated given 3 times a day with meals.

The recommended dose and frequency of metformin is:

  • Starting dose: 500 mg orally twice a day or 850 mg once a day
  • Dose increment: 500 mg weekly or 850 mg every 2 weeks
  • Maximum dose: 2550 mg per day, given in divided doses
  • Frequency for doses above 2000 mg: 3 times a day with meals 3

From the Research

Metformin Dose and Frequency

  • The dose and frequency of metformin can vary depending on the patient's condition and the specific treatment regimen.
  • According to the study 4, metformin was administered at a dose of 850 mg twice daily for six months.
  • Another study 5 mentions that metformin was added to failing sulphonylurea monotherapy at a dose of 850-2,550 mg/day.
  • The study 6 does not provide specific information on the dose and frequency of metformin, but it does mention that patients received pioglitazone plus metformin (Pio+Met) due to inadequate control with previous therapy.

Comparison with Other Treatments

  • The study 4 compares the effects of pioglitazone and metformin on endothelial function in patients with type 2 diabetes treated with sulfonylureas.
  • The study 5 examines the long-term effects of pioglitazone or gliclazide addition to failing metformin monotherapy and pioglitazone or metformin addition to failing sulphonylurea monotherapy in patients with type 2 diabetes.
  • The study 6 evaluates the changes in cardiovascular risk profile in patients with type 2 diabetes mellitus (T2DM) who started oral antihyperglycemic treatment with either pioglitazone plus a sulfonylurea, pioglitazone plus metformin, or a sulfonylurea plus metformin.
  • The study 7 investigates the risk of coronary artery disease, congestive heart failure, and overall mortality in type 2 diabetic patients receiving rosiglitazone, pioglitazone, metformin, or sulfonylureas.

Key Findings

  • Metformin induced a significant decrease in HbA(1C) 4.
  • Pioglitazone or metformin addition to failing sulphonylurea monotherapy improved glycaemic control and this improvement was sustained over 2 years 5.
  • Treatment with pioglitazone was associated with significant improvements of lipid and glycemic parameters that are linked to insulin resistance and cardiovascular risk in patients with T2DM 6.
  • Metformin was associated with a reduced risk of congestive heart failure and mortality when compared to sulfonylurea 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.