There is no fixed dosage regimen for the management of hyperglycemia in patients with type 2 diabetes with metformin HCl extended-release tablets, USP or any other pharmacologic agent. Dosage of metformin HCl extended-release tablets, USP 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 HCl extended-release tablets, USP in adults is 2000 mg.

Metformin HCl extended-release tablets, USP should generally be given once daily with the evening meal. Metformin HCl extended-release tablets, USP 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 HCl extended-release tablets, USP 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 HCl extended-release tablets, USP, 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 HCl extended-release tablets, USP may be sufficient during periods of transient loss of control in patients usually well-controlled on diet alone.

Metformin HClextended-release tablets, USP must be swallowed whole and never crushed or chewed. Occasionally, the inactive ingredients of metformin HCl extended-release tablets, USP will be eliminated in the feces as a soft, hydrated mass. (See Patient Information printed below.) 

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 HCl extended-release tablets, USP is 500 mg once daily with the evening meal. Dosage increases should be made in increments of 500 mg weekly, up to a maximum of 2000 mg once daily with the evening meal. If glycemic control is not achieved on metformin HCl extended-release tablets, USP 2000 mg once daily, a trial of metformin HCl extended-release tablets, USP 1000 mg twice daily should be considered. (See CLINICAL PHARMACOLOGY, Clinical Studies.) 

Pediatrics \- Safety and effectiveness of metformin HCl extended-release tablets, USP in pediatric patients have not been established. 

Transfer From Other Antidiabetic Therapy

When transferring patients from standard oral hypoglycemic agents other than chlorpropamide to metformin HCl extended-release tablets, USP, 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 HClExtended-Release Tablets, USP and Oral Sulfonylurea Therapy in Adult Patients

If patients have not responded to four weeks of the maximum dose of metformin HCl extended-release tablets, USP monotherapy, consideration should be given to gradual addition of an oral sulfonylurea while continuing metformin HCl extended-release tablets, USP 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 HCl extended-release tablets, USP and sulfonylurea therapy, the desired control of blood glucose may be obtained by adjusting the dose of each drug. With concomitant metformin HCl extended-release tablets, USP 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 HCl extended-release tablets, USP and the maximum dose of an oral sulfonylurea, consider therapeutic alternatives including switching to insulin with or without metformin HCl extended-release tablets, USP.

Concomitant Metformin HClExtended-Release Tablets, USP and Insulin Therapy in Adult Patients

The current insulin dose should be continued upon initiation of metformin HCl extended-release tablets, USP therapy. Metformin HCl extended-release tablets, USP therapy should be initiated at 500 mg once daily in patients on insulin therapy. For patients not responding adequately, the dose of metformin HCl extended-release tablets, USP 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 2000 mg for metformin HCl extended-release tablets, USP. 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 HCl extended-release tablets, USP. Further adjustment should be individualized based on glucose-lowering response.

Specific Patient Populations

Metformin HCl extended-release tablets, USP are not recommended for use in pregnancy. Metformin HCl extended-release tablets, USP are not recommended in pediatric patients (below the age of 17 years).

The initial and maintenance dosing of metformin HCl extended-release tablets, USP 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 HCl extended-release tablets, USP.

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