Teratogenic Effects: Pregnancy Category B.

Recent information strongly suggests that abnormal blood glucose levels during pregnancy are associated with a higher incidence of congenital abnormalities. Most experts recommend that insulin be used during pregnancy to maintain blood glucose levels as close to normal as possible. Because animal reproduction studies are not always predictive of human response, metformin hydrochloride tablets, USP and metformin hydrochloride extended-release tablets, USP should not be used during pregnancy unless clearly needed.

There are no adequate and well-controlled studies in pregnant women with metformin hydrochloride tablets, USP or metformin hydrochloride extended-release tablets, USP. Metformin was not teratogenic in rats and rabbits at doses up to 600 mg/kg/day. This represents an exposure of about two and six times the maximum recommended human daily dose of 2000 mg based on body surface area comparisons for rats and rabbits, respectively. Determination of fetal concentrations demonstrated a partial placental barrier to metformin.

Nursing Mothers

Studies in lactating rats show that metformin is excreted into milk and reaches levels comparable to those in plasma. Similar studies have not been conducted in nursing mothers. 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. If metformin hydrochloride tablets, USP or metformin hydrochloride extended-release tablets, USP are discontinued, and if diet alone is inadequate for controlling blood glucose, insulin therapy should be considered.

Pediatric Use

The safety and effectiveness of metformin hydrochloride tablets, USP for the treatment of type 2 diabetes have been established in pediatric patients ages 10 to 16 years (studies have not been conducted in pediatric patients below the age of 10 years). Use of metformin hydrochloride tablets, USP in this age group is supported by evidence from adequate and well-controlled studies of metformin hydrochloride tablets, USP in adults with additional data from a controlled clinical study in pediatric patients ages 10 to 16 years with type 2 diabetes, which demonstrated a similar response in glycemic control to that seen in adults. (See CLINICAL PHARMACOLOGY: Pediatric Clinical Studies.) In this study, adverse effects were similar to those described in adults. (See ADVERSE REACTIONS: Pediatric Patients.) A maximum daily dose of 2000 mg is recommended. (See DOSAGE AND ADMINISTRATION: Recommended Dosing Schedule: Pediatrics.)

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

Geriatric Use

Controlled clinical studies of metformin hydrochloride tablets, USP and metformin hydrochloride extended-release tablets, USP did not include sufficient numbers of elderly patients to determine whether they respond differently from younger patients, although other reported clinical experience has not identified differences in responses between the elderly and younger patients. Metformin is known to be substantially excreted by the kidney and because the risk of serious adverse reactions to the drug is greater in patients with impaired renal function, metformin hydrochloride tablets, USP, and metformin hydrochloride extended-release tablets, USP should only be used in patients with normal renal function (see CONTRAINDICATIONS, WARNINGS and CLINICAL PHARMACOLOGY: Pharmacokinetics). Because aging is associated with reduced renal function, metformin hydrochloride tablets, USP or metformin hydrochloride extended-release tablets, USP should be used with caution as age increases. Care should be taken in dose selection and should be based on careful and regular monitoring of renal function. Generally, elderly patients should not be titrated to the maximum dose of metformin hydrochloride tablets, USP or metformin hydrochloride extended-release tablets, USP (see also WARNINGS and DOSAGE AND ADMINISTRATION).

Please visit the FDA site for more information regarding using this drug in specific populations:   
http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=6249318a-dd65-4323-b501-386305aad059