Difference Between Glipizide and Metformin


Main Difference

The main difference between Glipizide and Metformin is that Glipizide is a hypoglycemic agent and Metformin is an antihyperglycemic agent.

Glipizide vs. Metformin

Glipizide is Sulfonylurea while Metformin is biguanide. Glipizide is used as a hypoglycemic agent, on the other hand, Metformin is used as an antihyperglycemic agent. Glipizide is used in Type 2 DM, while Metformin is used both in Type 1 DM and type 2 DM. Glipizide belongs to pregnancy category C while Metformin belongs to pregnancy category B. Glipizide is available as tablets whereas Metformin is available as tablets and oral solutions. Glipizide immediate-release tablets are available in the strength of 5mg,10 mg while Metformin immediate-release tablets are available in the strength of 500mg,800mg, and 1000mg. Glipizide extended-release tablets are available in the strength of 2.5mg, 5mg and 10mg whereas Metformin extended release tablets are available in the strength of 500mg,750mg, and 1000mg. Glipizide is not used in polycystic syndrome, while Metformin is used in polycystic syndrome.


Comparison Chart

Glipizide is a hypoglycemic agent which belongs to the second generation of Sulfonylureas.Metformin is biguanide and is an antihyperglycemic agent.
Mechanism of Action
Increase the release of insulin from beta cells of the pancreas.Complete mechanism not yet known
Drug Classification
Therapeutic Use
Hypoglycemic agentAntihyperglycemic agents
Strength of Immediate-Release Tablets
5mg, 10 mg500mg, 800mg, 1000mg
Strength of Extended-Release Tablets
2.5mg, 5mg, 10mg500mg, 750mg, 1000mg
Dosage Form
TabletsTablets, Solutions
Drug interactions
Oral Contraceptives

What is Glipizide?

Glipizide belongs to the second generation of Sulfonylureas, which cause the hypoglycemia when they stimulate the insulin release from the beta cells of the pancreas. Glipizide is prescribed to patients of type 2 DM as they increase the release from the pancreas. Glipizide acts on the beta cells of the pancreas and in the presence of Glipizide the beta cells of pancreas increases more insulin in response to glucose, so the action of Glipizide the beta cells of the pancreas must be functional. Glipizide partially blocks potassium channels of the beta cells in the pancreas, this leads to cell depolarization and opens the voltage-gated calcium channels, and it enhances insulin release from beta cells. Glipizide is a short-acting drug. Glipizide is not used in type 1 DM. Glipizide increases the levels of insulin as they reduce hepatic insulin clearance. Glipizide is used with a diabetic diet. Glipizide is taken orally. The pharmacological effects start to appear after the half hr of the dose, and pharmacological effects can be seen after one day of the dose. Glipizide has a short half-life. Adverse effects of Glipizide are a headache, low sugar levels, nausea, and diarrhea. Severe hypoglycemia caused by Glipizide may lead to a neurological emergency. Less common side effects are skin rash, shaking of the body, and sleepy feel. Glipizide dose is adjusted when a diabetic patient is also suffering from liver or kidney ailment as Glipizide is metabolized by the liver. Glipizide is excreted in urine both in the form of unchanged drug or in the form of metabolites. Glipizide use in pregnancy and breastfeeding mothers are not allowed. Glipizide tablets are available in the strength of 2.5mg to 10mg.



The most famous brand containing Glipizide is Glucotrol.

What is Metformin?

Metformin is the 1st the line treatment of type 2 diabetes. Metformin is biguanide and is antihyperglycemic, As Metformin does not cause the release of insulin from the pancreas, so it does not cause hypoglycemia. Metformin is orally taken. Metformin is especially beneficial for patients who are overweight. Metformin is also prescribed to the patients of polycystic ovary syndrome. The mechanism of action of the metformin is not known, but potential mechanisms have been proposed by clinicians. The ultimate result of all proposed mechanisms is that Metformin decreases gluconeogenesis. Metformin also increases the insulin sensitivity leading to an increase in the action of insulin on the muscle and fat cells. Metformin is available as the Metformin HCL which is completely soluble in water, insoluble in acetone and slightly soluble in ethanol. Metformin, when taken orally, shows bioavailability of 50%-60% and peak plasma concentration is reached into 1 to 3 hrs when immediate release Metformin is taken and 4 to 8 hrs when extended release Metformin is taken. A negligible amount of Metformin is bound to plasma proteins. Metformin shows many side effects like gastrointestinal irritations, metallic taste, and anorexia. The severe adverse effect of the Metformin is lactic acidosis. Metformin overdose causes tachycardia, vomiting, abdominal pain, and diarrhea. No specific antidote of Metformin is known. Metformin is excreted unchanged into urine. The maximum daily dose is 2.5 g, which is given in three divided doses with meals. Metformin shows drug interactions with many drugs such as anticholinergics and cimetidine, which is H2 receptor blocker. Metformin should not be given to patients who have impaired function of kidney and liver. Metformin should also be not given to patients of cardiac failure and chronic hypoxic lung disease.


Famous brand containing Metformin is Glucophage.

Key Differences

  1. Glipizide is classified as sulfonylureas while Metformin is classified as a biguanide.
  2. Glipizide shows its pharmacological actions as a hypoglycemic agent; on the other hand, Metformin shows its pharmacological actions as an antihyperglycemic agent.
  3. Glipizide is used to treat Type 2 DM while Metformin used to treat Type 2 DM and Type 1 DM.
  4. Glipizide on the other hand Metformin
  5. Glipizide is available in solid dosage form, whereas Metformin is available in the solid and liquid dosage form.
  6. Glipizide is classified as pregnancy category C; on the other hand, Metformin is classified as pregnancy category B.
  7. Glipizide does not find its therapeutic use in the treatment of polycystic syndrome, whereas Metformin is a therapeutic moiety to treat the polycystic syndrome.
  8. Glipizide increases insulin release, while Metformin does not increase insulin release.


The conclusion of the above discussion is that both Glipizide and Metformin are used in the treatment of Type 2 DM, but their mechanism of action is different from each other.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White