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Metformin (Metformin Hydrochloride) - Indications and Dosage

 
 



INDICATIONS AND USAGE

Metformin hydrochloride tablets, as monotherapy, are indicated as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes. Metformin is indicated in patients 10 years of age and older.

Metformin may be used concomitantly with a sulfonylurea or insulin to improve glycemic control in adults (17 years of age and older).

DOSAGE AND ADMINISTRATION

There is no fixed dosage regimen for the management of hyperglycemia in patients with type 2 diabetes with metformin or any other pharmacologic agent. Dosage of metformin 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 is 2550 mg in adults and 2000 mg in pediatric patients (10-16 years of age).

Metformin should be given in divided doses with meals. Metformin 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 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 a 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 may be sufficient during periods of transient loss of control in patients usually well-controlled on diet alone.

Recommended Dosing Schedule

Adults

In general, clinically significant responses are not seen at doses below 1500 mg per day. However, a lower recommended starting dose and gradually increased dosage is advised to minimize gastrointestinal symptoms.

The usual starting dose of metformin hydrochloride tablets is 500 mg twice a day or 850 mg once a day, given with meals. 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. 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 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

The usual starting dose of metformin hydrochloride tablets is 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.

Transfer from Other Antidiabetic Therapy

When transferring patients from standard oral hypoglycemic agents other than chlorpropamide to metformin, no transition period generally is necessary. When transferring patients from chlorpropamide, care should be exercised during the first two weeks because of the prolonged retention of chlorpropamide in the body, leading to overlapping drug effects and possible hypoglycemia.

Concomitant Metformin Hydrochloride and Oral Sulfonylurea Therapy in Adult Patients

If patients have not responded to four weeks of the maximum dose of metformin hydrochloride 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 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 500 mg and glyburide 20 mg were titrated to 1000/20 mg, 1500/20 mg, 2000/20 mg or 2500/20 mg of metformin and glyburide, respectively, to reach the goal of glycemic control as measured by 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 and sulfonylurea therapy, the risk of hypoglycemia associated with sulfonylurea therapy continues and may be increased. Appropriate precautions 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 and the maximum dose of an oral sulfonylurea, consider therapeutic alternatives including switching to insulin with or without metformin.

Concomitant Metformin and Insulin Therapy in Adult Patients

The current insulin dose should be continued upon initiation of metformin therapy.  Metformin therapy should be initiated at 500 mg once daily in patients on insulin therapy.  For patients not responding adequately, the dose of metformin 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. 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. Further adjustment should be individualized based on glucose-lowering response.

Specific Patient Populations

Metformin is not recommended for use in pregnancy. Metformin is 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. Generally, elderly, debilitated, and malnourished patients should not be titrated to the maximum dose of metformin hydrochloride tablets.

Monitoring of renal function is necessary to aid in prevention of lactic acidosis, particularly in the elderly. (See WARNINGS.)

HOW SUPPLIED

Metformin hydrochloride tablets

  500 mg      Bottles of 30          NDC 13668-001-30
  500 mg      Bottles of 60          NDC 13668-001-60
  500 mg      Bottles of 90          NDC 13668-001-90
  500 mg      Bottles of 100        NDC 13668-001-01
  500 mg      Bottles of 120        NDC 13668-001-12
  500 mg      Bottles of 500        NDC 13668-001-05
  500 mg      Bottles of 1000      NDC 13668-001-10

  850 mg      Bottles of 30         NDC 13668-002-30
  850 mg      Bottles of 60         NDC 13668-002-60
  850 mg      Bottles of 90         NDC 13668-002-90
  850 mg      Bottles of 100       NDC 13668-002-01
  850 mg      Bottles of 120       NDC 13668-002-12
  850 mg      Bottles of 500       NDC 13668-002-05

  1000 mg    Bottles of 30        NDC 13668-003-30
  1000 mg    Bottles of 60        NDC 13668-003-60
  1000 mg    Bottles of 90        NDC 13668-003-90
  1000 mg    Bottles of 100      NDC 13668-003-01
  1000 mg    Bottles of 120      NDC 13668-003-12
  1000 mg    Bottles of 500      NDC 13668-003-05

Metformin hydrochloride tablets USP 500 mg are white to off-white, round shaped, biconvex, film coated tablets with beveled edges, Torrent logo debossed on one side and ‘500’ on the other side.

Metformin hydrochloride tablets USP 850 mg are white to off-white, round shaped, biconvex, film coated tablets with beveled edges, Torrent logo debossed on one side and ‘850’ on the other side.

Metformin hydrochloride tablets USP 1000 mg are white to off-white, oblong shaped, biconvex, film coated tablets with break line on both sides, Torrent logo debossed on one side and ‘1000’ on the other 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 a light-resistant container.

8008587
torrent

Manufactured by:

TORRENT PHARMACEUTICALS LTD., Indrad-382 721, Dist. Mehsana, India.

For:

TORRENT PHARMA INC., 5380 Holiday Terrace, Suite 40, Kalamazoo, Michigan 49009.

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