E.R. tablet Metformin 500mg

Generic Name of ProductBrand NameDosage Form StrengthPharmacologic GroupTherapeutic GroupUnit Per Pack
MetforminMetfoxirE.R.tablet5000mg/1000mgAntidiabetic agent - BiguanideAntidiabetic100

Indications And Usage

Metfoxir is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus



Swallow Metfoxir whole and never crush, cut or chew.

The recommended starting dose of Metfoxir is 500 mg orally once daily with the evening meal.

Increase the dose in increments of 500 mg weekly on the basis of glycemic control and tolerability, up to a maximum of 2,000 mg once daily with the evening meal.

If glycemic control is not achieved with Metfoxir 2,000 mg once daily, consider a trial of Metfoxir 1,000 mg twice daily.

Patients receiving metformin hydrochloride (HCl) may be switched to Metfoxir once daily at the same total daily dose, up to 2,000 mg once daily.2*


The FDA revised its prescribing information on metformin in 2016.

Metformin is contraindicated in people with:

severe renal impairment (estimated glomerular filtration rate (eGFR) below 30 ml/min/1.73 m2), known hypersensitivity to metformin, acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma.

Warnings are also given regarding the use of metformin in less severe renal impairment, people aged 65 years old or greater, hypoxic states (e.g., acute congestive heart failure), excessive alcohol intake, hepatic impairment, concomitant use of certain drugs (e.g. carbonic anhydrase inhibitors such as topiramate ), surgery, and other procedures, or in people having a radiological study with administration of an iodinated contrast agent.

Metformin is recommended to be temporarily discontinued before any procedure involving use of iodinated contrast agents, (such as a contrast-enhanced CT scan or angiogram) due to the increased risk of lactic acidosis resulting from impaired kidney function metformin can be resumed after two days after contrast administration, if renal function is adequate and stable.1*


Alcohol—Drinking alcohol may cause severe low blood sugar. Discuss this with your health care team.

Other medicines—Do not take other medicines unless they have been discussed with your doctor. This especially includes nonprescription medicines such as aspirin, and medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems.

Under certain conditions, too much metformin can cause lactic acidosis

Adverse Reactions

The most common adverse effect of metformin is gastrointestinal irritation, including diarrhea, cramps, nausea, vomiting, and increased flatulence; metformin is more commonly associated with gastrointestinal side effects than most other antidiabetic medications. The most serious potential side effect of metformin use is lactic acidosis; this complication is very rare, and the vast majority of these cases seem to be related to comorbid conditions, such as impaired liver or kidney function, rather than to the metformin itself.1*

Pregnancy and lactation

Pregnancy :Risk Summary

Limited data with Metfoxir in pregnant women are not sufficient to determine a drug-associated risk for major birth defects or miscarriage. Published studies with metformin use during pregnancy have not reported a clear association with metformin and major birth defect or miscarriage risk [see Data]. There are risks to the mother and fetus associated with poorly controlled diabetes mellitus in pregnancy.

Lactation :Risk Summary

Limited published studies report that metformin is present in human milk [see Data]. However, there is insufficient information to determine the effects of metformin on the breastfed infant and no available information on the effects of metformin on milk production. Therefore, the developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for Metfoxir and any potential adverse effects on the breastfed child from Metfoxir or from the underlying maternal condition.

Renal and liver Impairment

Metformin reduces liver (hepatic) production of glucose, decreases the intestinal absorption of glucose, and enhances insulin sensitivity by increasing both peripheral glucose uptake and utilization.

Laboratory Tests

Vitamin B12 Concentrations.

In clinical trials of 29-week duration with metformin HCl tablets, a decrease to subnormal levels of previously normal serum vitamin B12 levels was observed in approximately 7% of patients.