Glucofage: Chemical Formula, Indications, Dosage, Side Effects, Warnings, Contraindications and Interactions

Biguanides prevent the liver from producing glucose, causing a decrease in the levels present in the bloodstream.

The active ingredient in glucophage is metformin . Metformin is a drug that is classified according to its pharmacological characteristics within oral antidiabetic agents , while according to its chemical characteristics it is classified as biguanides.

Chemical formula of glucophage

  • C4H11N5.


  • Coated tablets of 500 and 850 mg.

Indications for glucophage

Glucophage is used only for the treatment of type 2 diabetes mellitus and is the drug of choice for the treatment of diabetes .

Clinical studies have shown that this drug reduces the risk of complications in patients with diabetes such as nephropathy and retinopathy .

Mechanism of action

It works by decreasing glucose synthesis in the liver, but it does not stimulate insulin secretion.

Due to this mechanism of action, this drug rarely causes hypoglycemia unlike other antidiabetic drugs.

Glucophage improves insulin sensitivity by increasing peripheral glucose uptake and utilization of muscle and fat cells.


The dose depends on the blood glucose levels. The starting dose is usually 500 mg 2 or 3 times a day and can be increased two weeks after starting therapy, if necessary.

Glucophage works best if it is taken with a meal or immediately after a meal. It should never be used in children under 10 years of age.

The maximum daily dose of glucophage is 3 grams. If you take this medicine once a day, it is best to take it with breakfast. If you take this medicine twice a day, it is best to take it with breakfast and dinner.

Side effects of glucophage

Glucophage side effects commonly resolve after a few days.

Possible side effects of glucofage include:

  • Nausea, vomiting, abdominal pain, diarrhea and other stomach problems, these effects happen very often.
  • Food taste changes that occur often.
  • Lactic acidosis, this is a side effect that occurs very rarely due to the use of glucophage (only 1 in 10,000 patients experience this side effect), this is a condition characterized by an increase in the level of lactic acid in the blood. Lactic acidosis is best treated with hemodialysis .
  • Megaloblastic anemia , this occurs because metformin reduces the absorption of vitamin B12 in the body.
  • Hepatitis.
  • Chills, bluish skin, irregular heartbeat, or trouble breathing.

Warnings and Contraindications

Lactic acidosis occurs more frequently in patients with impaired liver or kidney function, and the use of glucophage in such patients should be carefully implemented.

The use of large doses of this medicine is associated with an increased risk of lactic acidosis.

Glycophage rarely causes hypoglycemia, if used individually. The risk of hypoglycemia is higher in patients who eat less and exercise more.

Clinical studies have shown that glucophage is safe for the treatment of gestational diabetes, which is a form of diabetes that occurs during pregnancy.

Glucophage is recommended as a first-line drug for the prevention of complications during pregnancy.

However, there are no guidelines on what dosage pregnant women should take and for how long.

Some research suggests that glucophage is not used during the first three months of pregnancy and that other antidiabetic medications such as insulin and glyburide are best used during this period.

In clinical studies, the use of glucophage in pregnant women who have PCOS reduced the risk of preterm delivery and miscarriage.

Glucophage should be administered with caution to nursing mothers, as it is excreted in human milk.

Glycophage interactions

Concomitant administration with other antidiabetic drugs increases the risk of hypoglycaemia.

Glucophage enters into significant interactions with the following medications:

  1. Diatrizoate and metrizamide, which are X-ray contrast agents.
  2. Lotalamate, iodixanol, iopamidol and ioversol, which are radiocontrast agents.
  3. Fluoroquinolone antibiotics such as Gatifloxacin. Co-administration of these drugs increases the risk of hypoglycemia.

Metformin can also interact with the following medications:

  • Anti-asthmatics such as Salbutamol.
  • Corticosteroids.
  • Diuretics.