Metformin instructions for administration
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Instructions For Administration
GLUCOPHAGE
GLUCOPHAGE XR
Switching from GLUCOPHAGE to GLUCOPHAGE XR
Transfer From Other Antidiabetic Therapy
Concomitant GLUCOPHAGE or GLUCOPHAGE XR and Oral Sulfonylurea Therapy
Concomitant GLUCOPHAGE or GLUCOPHAGE XR and Insulin Therapy
Specific Patient Populations
GLUCOPHAGE
The usual starting dose of GLUCOPHAGE (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,
GLUCOPHAGE 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. Return to top
GLUCOPHAGE XR
The usual starting dose of GLUCOPHAGE XR (metformin hydrochloride extendedrelease
tablets) 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 GLUCOPHAGE XR 2000 mg once
daily, a trial of GLUCOPHAGE XR 1000 mg twice daily should be considered. If higher
doses of metformin are required, GLUCOPHAGE should be used at total daily doses up to
2550 mg administered in divided daily doses, as described above. Return to top
Switching from GLUCOPHAGE to GLUCOPHAGE XR
In a randomized trial, patients currently treated with GLUCOPHAGE were switched to
GLUCOPHAGE XR. Results of this trial suggest that patients receiving GLUCOPHAGE
treatment may be safely switched to GLUCOPHAGE XR once daily at the same total
daily dose, up to 2000 mg once daily. Following a switch from GLUCOPHAGE to
GLUCOPHAGE XR, glycemic control should be closely monitored and dosage
adjustments made accordingly. Return to top
Transfer From Other Antidiabetic Therapy
When transferring patients from standard oral hypoglycemic agents other than
chlorpropamide to GLUCOPHAGE or GLUCOPHAGE XR, 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. Return to top
Concomitant GLUCOPHAGE or GLUCOPHAGE XR and Oral Sulfonylurea Therapy
If patients have not responded to four weeks of the maximum dose of
GLUCOPHAGE or GLUCOPHAGE XR monotherapy, consideration should be given
to gradual addition of an oral sulfonylurea while continuing GLUCOPHAGE or
GLUCOPHAGE XR 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).If patients have not satisfactorily responded to one to three months of concomitant
therapy with the maximum dose of GLUCOPHAGE or GLUCOPHAGE XR and the
maximum dose of an oral sulfonylurea, consider therapeutic alternatives including
switching to insulin with or without GLUCOPHAGE or GLUCOPHAGE XR. Return to top
Concomitant GLUCOPHAGE or GLUCOPHAGE XR and Insulin Therapy
The current insulin dose should be continued upon initiation of GLUCOPHAGE or
GLUCOPHAGE XR therapy. GLUCOPHAGE or GLUCOPHAGE XR therapy should
be initiated at 500 mg once daily in patients on insulin therapy. For patients not
responding adequately, the dose of GLUCOPHAGE or GLUCOPHAGE XR 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 GLUCOPHAGE and 2000 mg for GLUCOPHAGE XR. 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 GLUCOPHAGE or GLUCOPHAGE XR. Further adjustment should be
individualized based on glucose-lowering response. Return to top
Specific Patient Populations
GLUCOPHAGE or GLUCOPHAGE XR are not recommended for use in pregnancy or
for use in pediatric patients.
The initial and maintenance dosing of GLUCOPHAGE or GLUCOPHAGE XR 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 GLUCOPHAGE or GLUCOPHAGE XR.
Monitoring of renal function is necessary to aid in prevention of lactic acidosis,
particularly in the elderly. Return to top
Adapted from the FDA Package Insert.