Metarin (Metformin Hydrochloride tablet) is indicated as an adjunct to diet and exercise to improve glycemic control in children and adults with type-2 diabetes mellitus.
Metarin XR (Metformin Hydrochloride extended release tablet) is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type-2 diabetes mellitus.
Dosage & Administration
Dosage of Metarin or Metarin XR must be individualized on the basis of both effectiveness and tolerance, while not exceeding the maximum recommended daily dose. The maximum recommended daily dose of Metarin is 2550 mg in adults and 2000 mg in pediatric patients (10-16 years of age); the maximum recommended daily dose of Metarin XR in adults is 2000 mg. Metarin should be given in divided doses with meals while Metarin XR should generally be given once daily with the evening meal. Metarin XR tablet must be swallowed whole and never be crushed or chewed. Metarin or Metarin XR 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. Recommended Dosing Schedule Adults: The usual starting dose of Metarin 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. Doses above 2000 mg may be better tolerated given three times a day with meals. The usual starting dose of Metarin XR 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 Metarin XR 2000 mg once daily, a trial of Metarin XR 1000 mg twice daily should be considered. Patients receiving Metarin treatment may be safely switched to Metarin XR once daily at the same total daily dose, up to 2000 mg once daily. Pediatrics: The usual starting dose of Metarin 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. Safety and effectiveness of Metarin in pediatric patients below 10 years have not been established. Use in Pregnancy & Lactation Metformin Pregnancy Category B. Most experts recommend that insulin should be used during pregnancy to maintain blood glucose levels as close to normal as possible. Both Metformin immediate and extended release tablets should not be used during pregnancy unless clearly needed. Because the potential for hypoglycemia in nursing infants may exist, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Lactic acidosis can occur due to Metformin accumulation during treatment with Metformin. The reported incidence of lactic acidosis in patients receiving Metformin is very low. Metformin is known to be substantially excreted by the kidney and the risk of Metformin accumulation and lactic acidosis increases with the degree of impairment of renal function. Thus, patients with serum creatinine levels above the upper limit of normal for their age should not receive Metformin. In patients with advanced age, Metformin should be carefully titrated to establish the minimum dose for adequate glycemic effect, because aging is associated with reduced renal function.