General Considerations
Dosage of Glyburide and Metformin Hydrochloride must be individualized on the basis of both effectiveness and tolerance while not exceeding the maximum recommended daily dose of 20 mg glyburide/2000 mg metformin. Glyburide and Metformin Hydrochloride should be given with meals and should be initiated at a low dose, with gradual dose escalation as described below, in order to avoid hypoglycemia (largely due to glyburide), to reduce GI side effects (largely due to metformin), and to permit determination of the minimum effective dose for adequate control of blood glucose for the individual patient.
With initial treatment and during dose titration, appropriate blood glucose monitoring should be used to determine the therapeutic response to Glyburide and Metformin Hydrochloride and to identify the minimum effective dose for the patient. Thereafter, HbA1c should be measured at intervals of approximately 3 months to assess the effectiveness of therapy. The therapeutic goal in all patients with type 2 diabetes is to decrease FPG, PPG, and HbA1c to normal or as near normal as possible. Ideally, the response to therapy should be evaluated using HbA1c (glycosylated hemoglobin), which is a better indicator of long-term glycemic control than FPG alone.
No studies have been performed specifically examining the safety and efficacy of switching to Glyburide and Metformin Hydrochloride therapy in patients taking concomitant glyburide (or other sulfonylurea) plus metformin. Changes in glycemic control may occur in such patients, with either hyperglycemia or hypoglycemia possible. Any change in therapy of type 2 diabetes should be undertaken with care and appropriate monitoring.
Glyburide and Metformin Hydrochloride in Patients with Inadequate Glycemic Control on Diet and Exercise
Recommended starting dose: 1.25 mg/250 mg once or twice daily with meals.
For patients with type 2 diabetes whose hyperglycemia cannot be satisfactorily managed with diet and exercise alone, the recommended starting dose of Glyburide and Metformin Hydrochloride is 1.25 mg/250 mg once a day with a meal. As initial therapy in patients with baseline HbA1c >9% or an FPG >200 mg/dL, a starting dose of Glyburide and Metformin Hydrochloride 1.25 mg/250 mg twice daily with the morning and evening meals may be used. Dosage increases should be made in increments of 1.25 mg/250 mg per day every two weeks up to the minimum effective dose necessary to achieve adequate control of blood glucose. In clinical trials of Glyburide and Metformin Hydrochloride as initial therapy, there was no experience with total daily doses greater than 10 mg/2000 mg per day. Glyburide and Metformin Hydrochloride 5 mg/500 mg should not be used as initial therapy due to an increased risk of hypoglycemia.
Glyburide and Metformin Hydrochloride Use in Patients with Inadequate Glycemic Control on a Sulfonylurea and/or Metformin
Recommended starting dose: 2.5 mg/500 mg or 5 mg/500 mg twice daily with meals.
For patients not adequately controlled on either glyburide (or another sulfonylurea) or metformin alone, the recommended starting dose of Glyburide and Metformin Hydrochloride is 2.5 mg/500 mg or 5 mg/500 mg twice daily with the morning and evening meals. In order to avoid hypoglycemia, the starting dose of Glyburide and Metformin Hydrochloride should not exceed the daily doses of glyburide or metformin already being taken. The daily dose should be titrated in increments of no more than 5 mg/500 mg up to the minimum effective dose to achieve adequate control of blood glucose or to a maximum dose of 20 mg/2000 mg per day.
For patients previously treated with combination therapy of glyburide (or another sulfonylurea) plus metformin, if switched to Glyburide and Metformin Hydrochloride, the starting dose should not exceed the daily dose of glyburide (or equivalent dose of another sulfonylurea) and metformin already being taken. Patients should be monitored closely for signs and symptoms of hypoglycemia following such a switch and the dose of Glyburide and Metformin Hydrochloride should be titrated as described above to achieve adequate control of blood glucose.
Addition of Thiazolidinediones to Glyburide and Metformin Hydrochloride Therapy
For patients not adequately controlled on Glyburide and Metformin Hydrochloride, a thiazolidinedione can be added to Glyburide and Metformin Hydrochloride therapy. When a thiazolidinedione is added to Glyburide and Metformin Hydrochloride therapy, the current dose of Glyburide and Metformin Hydrochloride can be continued and the thiazolidinedione initiated at its recommended starting dose. For patients needing additional glycemic control, the dose of the thiazolidinedione can be increased based on its recommended titration schedule. The increased glycemic control attainable with Glyburide and Metformin Hydrochloride plus a thiazolidinedione may increase the potential for hypoglycemia at any time of day.
In patients who develop hypoglycemia when receiving Glyburide and Metformin Hydrochloride and a thiazolidinedione, consideration should be given to reducing the dose of the glyburide component of Glyburide and Metformin Hydrochloride. As clinically warranted, adjustment of the dosages of the other components of the antidiabetic regimen should also be considered.
Specific Patient Populations
Glyburide and Metformin Hydrochloride is not recommended for use during pregnancy. The initial and maintenance dosing of Glyburide and Metformin Hydrochloride should be conservative in patients with advanced age, due to the potential for decreased renal function in this population. Any dosage adjustment requires a careful assessment of renal function. Generally, elderly, debilitated, and malnourished patients should not be titrated to the maximum dose of Glyburide and Metformin Hydrochloride to avoid the risk of hypoglycemia. Monitoring of renal function is necessary to aid in prevention of metformin-associated lactic acidosis, particularly in the elderly. (See WARNINGS.)
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