From the Guidelines
The equivalent regular dose of Metformin 750 mg twice daily (bid) is Metformin 1500 mg per day, which can be taken as 500 mg three times daily (tid) or as 750 mg twice daily. Both dosing regimens deliver the same total daily dose of 1500 mg. The twice-daily regimen may be preferred for improved patient adherence since fewer daily doses are generally easier to remember. Metformin, a biguanide antihyperglycemic agent, works by decreasing hepatic glucose production, reducing intestinal glucose absorption, and improving insulin sensitivity 1. When changing between these equivalent regimens, patients should be advised to take metformin with meals to minimize gastrointestinal side effects such as nausea, diarrhea, and abdominal discomfort. The timing of doses should be spread throughout the day to maintain consistent blood levels of the medication for optimal glycemic control. It is essential to note that the maximum effective dose can be up to 1,000 mg twice per day, but is often 850 mg twice per day, and modestly greater effectiveness has been observed with doses up to about 2,500 mg/day 1. However, gastrointestinal side effects may limit the dose that can be used. Given the high efficacy, low cost, and minimal hypoglycemia risk of metformin, it remains the first-line medication for management of type 2 diabetes 1. Patients should be monitored for potential side effects, including lactic acidosis, and the medication should be omitted in the setting of severe illness, vomiting, or dehydration. Additionally, metformin may result in lower serum vitamin B12 concentration, and periodic monitoring and supplementation may be necessary if levels are deficient, particularly in those with anemia or neuropathy 1. It is crucial to consider the patient's kidney function when prescribing metformin, as it is cleared by the kidneys, and its use is restricted in patients with chronic kidney disease (CKD) 1. The exact GFR cutoff for metformin use to avoid lactic acidosis is controversial, but it is recommended to reevaluate metformin use when GFR is 45 mL/min/1.73 m2 and stop when 30 mL/min/1.73 m2 1. Overall, metformin is a highly effective and safe medication for the management of type 2 diabetes, and its equivalent regular dose of 1500 mg per day can be taken in various regimens to optimize patient adherence and glycemic control.
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.
The equivalent regular dose of Metformin 750 mg twice daily (bid) is 1500 mg per day, given in divided doses. This dose is within the recommended maximum dose of 2550 mg per day 2.
- Key points:
- The dose of 750 mg bid is not a standard starting dose, but it is within the recommended dosing range.
- The maximum dose of 2550 mg per day can be given in divided doses, and 1500 mg per day is below this maximum.
From the Research
Equivalent Regular Dose of Metformin
The equivalent regular dose of Metformin 750 mg twice daily (bid) can be determined by considering the total daily dose.
- The total daily dose of Metformin 750 mg bid is 1500 mg per day.
- According to the study 3, the usual effective dosage of Metformin is 1.5-2.5 g/day orally in two or three divided doses.
- This means that the total daily dose of 1500 mg falls within the recommended effective dosage range.
Comparison with Other Studies
- A study 4 suggests that a maximum daily dose of 2250,1700,1250,1000, and 500 mg in patients with normal kidney function, CKD stage 2, 3a, 3b, and 4, respectively, will provide a reasonable probability of achieving efficacy and safety.
- Another study 5 compared the dose and side effect profile of Metformin Extended Release (MXR) versus Metformin Immediate Release (MIR) and found that MXR has better gastrointestinal tolerability and fewer side effects compared to MIR, with similar efficacy regarding anti-hyperglycemic effects.
- A study 6 assessed the safety and tolerability of remogliflozin etabonate when administered with a total daily dose of 2000 mg of Metformin and found that co-administration was well tolerated in all subjects during the observation period.
Key Points
- The equivalent regular dose of Metformin 750 mg bid is 1500 mg per day.
- This dose falls within the recommended effective dosage range of 1.5-2.5 g/day orally in two or three divided doses 3.
- The dose is also consistent with the maximum daily dose recommended for patients with normal kidney function or CKD stage 2 4.