OverviewDosageSide EffectsInteractionsHalf-Life

Below are the general guidelines for dosing metformin. Note that these dosages may be adjusted on a case-by-case basis for individual patients. Always follow your prescribing physician’s instructions for taking metformin.

The following information comes from DailyMed, an FDA label information provider.

What if I miss a dose of metformin?

According to Mayo Clinic, if you miss a dose of metformin, take it right away unless you are closer in time to your next dose. If the latter is true, wait until your next dose. Never double up on doses.

What if I overdose on metformin?

Overdose of metformin hydrochloride has occurred, including ingestion of amounts greater than 50 grams. Hypoglycemia was reported in approximately 10% of cases, but no causal association with metformin hydrochloride has been established. Lactic acidosis has been reported in approximately 32% of metformin overdose cases (see WARNINGS). Metformin is dialyzable with a clearance of up to 170 mL/min under good hemodynamic conditions. Therefore, hemodialysis may be useful for removal of accumulated drug from patients in whom metformin overdosage is suspected.

Dosage and Administration

There is no fixed dosage regimen for the management of hyperglycemia in patients with type 2 diabetes with metformin hydrochloride tablets or any other pharmacologic agent. Dosage of metformin hydrochloride tablets must be individualized on the basis of both effectiveness and tolerance, while not exceeding the maximum recommended daily doses. The maximum recommended daily dose of metformin hydrochloride tablets are 2550 mg in adults and 2000 mg in pediatric patients (10-16 years of age). There is no FDA dose for children <10 years of age.

Metformin hydrochloride tablets should be given in divided doses with meals. Metformin hydrochloride tablets should be started at a low dose, with gradual dose escalation, both to reduce gastrointestinal side effects and to permit identification of the minimum dose required for adequate glycemic control of the patient.

During treatment initiation and dose titration (see RECOMMENDED DOSING SCHEDULE), fasting plasma glucose should be used to determine the therapeutic response to metformin hydrochloride tablets and identify the minimum effective dose for the patient. Thereafter, glycosylated hemoglobin should be measured at intervals of approximately three months. The therapeutic goal should be to decrease both fasting plasma glucose and glycosylated hemoglobin levels to normal or near normal by using the lowest effective dose of metformin hydrochloride tablets, either when used as monotherapy or in combination with sulfonylurea or insulin.

Monitoring of blood glucose and glycosylated hemoglobin will also permit detection of primary failure, i.e., inadequate lowering of blood glucose at the maximum recommended dose of medication, and secondary failure, i.e., loss of an adequate blood glucose lowering response after an initial period of effectiveness.

Short-term administration of metformin hydrochloride tablets may be sufficient during periods of transient loss of control in patients usually well-controlled on diet alone.

Adults

Adults
The usual starting dose of metformin hydrochloride tablets is 500 mg twice a day or 850 mg once a day, given with meals. In general, clinically significant responses are not seen at doses below 1500 mg per day. Dosage increases should be made in increments of 500 mg weekly or 850 mg every 2 weeks, up to a total of 2000 mg per day, given in divided doses. The dosage of metformin hydrochloride tablets must be individualized on the basis of both effectiveness and tolerability. Patients can also be titrated from 500 mg twice a day to 850 mg twice a day after 2 weeks. For those patients requiring additional glycemic control, metformin hydrochloride tablets may be given to a maximum daily dose of 2550 mg per day. Doses above 2000 mg may be better tolerated given three times a day with meals.

Pediatrics (Children 10 years or older)


The usual starting dose of metformin hydrochloride tablets are 500 mg twice a day, given with meals. Dosage increases should be made in increments of 500 mg weekly up to a maximum of 2000 mg per day, given in divided doses. The dosage of metformin hydrochloride tablets must be individualized on the basis of both effectiveness and tolerability.

Recommendations for Use in Renal Impairment

Assess renal function prior to initiation of metformin hydrochloride tablets and periodically thereafter.

Metformin hydrochloride tablets is contraindicated in patients with an estimated glomerular filtration rate (eGFR) below 30 mL/minute/1.73 m2 .

Initiation of metformin hydrochloride tablets in patients with an eGFR between 30 – 45 mL/minute/1.73 m2 is not recommended.

In patients taking metformin hydrochloride tablets whose eGFR later falls below 45 mL/min/1.73 m2, assess the benefit risk of continuing therapy.

Discontinue metformin hydrochloride tablets if the patient’s eGFR later falls below 30 mL/minute/1.73 m2 (See WARNINGS and PRECAUTIONS).

Discontinuation for Iodinated Contrast Imaging Procedures

Discontinue metformin hydrochloride tablets at the time of, or prior to, an iodinated contrast imaging procedure in patients with an eGFR between 30 and 60 mL/min/1.73 m2; in patients with a history of liver disease, alcoholism, or heart failure; or in patients who will be administered intra-arterial iodinated contrast. Re-evaluate eGFR 48 hours after the imaging procedure; restart metformin hydrochloride tablets if renal function is stable.

Concomitant Metformin hydrochloride tablets and Oral Sulfonylurea Therapy in Adult Patients

If patients have not responded to four weeks of the maximum dose of metformin hydrochloride tablets monotherapy, consideration should be given to gradual addition of an oral sulfonylurea while continuing metformin hydrochloride tablets at the maximum dose, even if prior primary or secondary failure to a sulfonylurea has occurred. Clinical and pharmacokinetic drug-drug interaction data are currently available only for metformin plus glyburide (glibenclamide).

With concomitant metformin hydrochloride tablets and sulfonylurea therapy, the desired control of blood glucose may be obtained by adjusting the dose of each drug. In a clinical trial of patients with type 2 diabetes and prior failure on glyburide, patients started on metformin hydrochloride 500 mg and glyburide 20 mg were titrated to 1000/20 mg, 1500/20 mg, 2000/20 mg or 2500/20 mg of metformin hydrochloride and glyburide, respectively, to reach the goal of glycemic control as measured by fasting blood glucose (FPG), HbA1c and plasma glucose response (see CLINICAL PHARMACOLOGY: CLINICAL STUDIES).

However, attempts should be made to identify the minimum effective dose of each drug to achieve this goal. With concomitant metformin hydrochloride tablets and sulfonylurea therapy, the risk of hypoglycemia associated with sulfonylurea therapy continues and may be increased. Appropriate pre¬cautions should be taken. (See Package Insert of the respective sulfonylurea.)

If patients have not satisfactorily responded to one to three months of concomitant therapy with the maximum dose of metformin hydrochloride tablets and the maximum dose of an oral sulfonylurea, consider therapeutic alternatives including switching to insulin with or without metformin hydrochloride tablets.

Concomitant Metformin hydrochloride tablets and Insulin Therapy in Adult Patients

The current insulin dose should be continued upon initiation of metformin hydrochloride tablets therapy. Metformin hydrochloride tablets therapy should be initiated at 500 mg once daily in patients on insulin therapy. For patients not responding adequately, the dose of metformin hydrochloride tablets should be increased by 500 mg after approximately 1 week and by 500 mg every week thereafter until adequate glycemic control is achieved. The maximum recommended daily dose is 2500 mg for metformin hydrochloride tablets. It is recommended that the insulin dose be decreased by 10% to 25% when fasting plasma glucose concentrations decrease to less than 120 mg/dL in patients receiving concomitant insulin and metformin hydrochloride tablets. Further adjustment should be individualized based on glucose-lowering response.

Specific Patient Populations

Metformin hydrochloride tablets are not recommended for use in pregnancy. Metformin hydrochloride tablets are not recommended in patients below the age of 10 years.

The initial and maintenance dosing of metformin hydrochloride tablets should be conservative in patients with advanced age, due to the potential for decreased renal function in this population. Any dosage adjustment should be based on a careful assessment of renal function.

How is Metformin supplied?

Metformin hydrochloride tablets, USP

500 mgBottles of 100NDC 24724-014-01
500 mgBottles of 500NDC 24724-014-50
850 mgBottles of 100NDC 24724-015-01
850 mgBottles of 500NDC 24724-015-50
1000 mgBottles of 100NDC 24724-016-01
1000 mgBottles of 500NDC 24724-016-50

Metformin hydrochloride tablets, 500mg are white to off white, round shaped, biconvex, film coated tablets debossedwith ‘I45’ on one side and plain on the other side.

Metformin hydrochloride tablets, 850mg are white to off white, capsule shaped, biconvex, film coated tabletsdebossed with ‘I46’ on one side and plain on other side.

Metformin hydrochloride tablets, 1000mg are white to off white, oval shaped, biconvex, film coated tablets debossedwith ‘I’ and ‘47’ separated by a breakline on one side and the breakline on theother side 

Storage


Store at 20°–25° C (68°–77° F); excursions permitted to 15°–30° C (59°–86° F). [See USP Controlled Room Temperature.]

Dispense in light-resistant containers. 

Manufactured by:
USV PRIVATE LIMITED
H-13, 16, 16A, 17, 18, 19, 20, 21 & E22, OIDC,
Mahatma Gandhi Udyog Nagar,
Dabhel, Daman 396210. India.

Manufactured for:
INDICUS PHARMA
Indicus Pharma LLC,
12308 Richmond Run Drive,
Raleigh, NC 27614                              

Disclaimer: this article does not constitute or replace medical advice. If you have an emergency or a serious medical question, please contact a medical professional or call 911 immediately. To see our full medical disclaimer, visit our Terms of Use page.


More about Metformin

Written by

Medically reviewed by