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Metformin is an antidiabetic medication, it acts primarily by decreasing endogenous hepatic glucose production (gluconeogenesis). Metformin also decreases intestinal absorption of glucose, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization.
Metformin lowers both basal and postprandial plasma glucose and unlike sulfonylureas, it is not associated with substantial risk for hypoglycemia.
Metformin as monotherapy remains the only agent associated with weight loss in patients with obesity with non-insulin-dependent diabetes mellitus (NIDDM). The mechanism may be attributed to decreased food intake [1].
Metformin is currently considered to be one of the first-choice drugs for type 2 diabetes mellitus, in particular, in overweight and obese people.
Metformin also has neutral to positive effects on LDL cholesterol and triglyceride levels.


Metformin is indicated as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes mellitus.

[edit] DOSAGE

Dosage should be individualized, based on the patient’s current regimen, effectiveness and tolerability.

In adults, the usual dose for Normal Tablets is 500 mg three or four times a day, or 850 mg two or three times a day. The maximum recommended daily dose for normal tablets is 2550 mg.

The usual starting dose of Extended-Release Tablets 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.

Metformin should be taken with food, or just after food, to reduce gastrointestinal symptoms.


  • Known hypersensitivity to Metformin
  • Renal impairment (e.g., serum creatinine levels ≥1.5 mg/dL for men, ≥1.4 mg/dL for women or abnormal creatinine clearance). Risk of metformin accumulation and lactic acidosis increases with the degree of impairment.
  • Patients suffering from severe hepatic dysfunction, since severe hepatic dysfunction has been associated with some cases of lactic acidosis.
  • Metabolic acidosis including diabetic ketoacidosis with or without coma. (Diabetic ketoacidosis should be treated with insulin)
  • Intravascular administration of iodinated contrast agents (it can lead to acute alteration of renal function and have been associated with lactic acidosis in patients receiving metformin)
  • During pregnancy and breastfeeding


  • Lactic acidosis is a very rare (0.03 cases/1000 patient/year), but serious, metabolic complication that can occur due to metformin accumulation (primarily reported in diabetic patients with significant renal failure). The risk increases also with conditions such as sepsis, dehydration, excess alcohol intake, hepatic impairment, and acute congestive heart failure. Symptoms include respiratory distress, abdominal pain , malaise, myalgias, increasing somnolence and hypothermia. If metabolic acidosis is suspected, treatment with the medicinal product should be discontinued and the patient hospitalised immediately.
  • Avoid excessive alcohol intake



  • Pregnancy Category B (US). Metformin should be used during pregnancy only if clearly needed.
    Most experts recommend that insulin be used during pregnancy to maintain blood glucose levels as close to normal as possible.
  • In nursing mothers, 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


Common adverse reactions reported in ≥5% of patients treated with Metformin were: Diarrhea, Nausea, vomiting, flatulence, asthenia, indigestion, abdominal discomfort and headache

Lactic acidosis is rare but serious. The symptoms are feeling weak, muscle pain, cold, breathing problems, dizziness, slow or irregular heartbeat. (See precautions)


Understanding Type 2 Diabetes
A simple explanation of what diabetes is



Diabetes (Antidiabetic drugs)
Insulin Secretagogues (drugs that increase insulin release from pancreas) Sulfonylureas Chlorpropamide (Diabinese)   Glibenclamide or Glyburide (Diabeta, Micronase, Glynase, Daonil, Euglycon)   Gliclazide (Diamicron)   Glimepiride (Amaryl, Solosa)   Glipizide (Glucotrol, Minidiab, Glibenese)   Gliquidone (Glurenorm)
Meglitinides Repaglinide (Prandin, Novonorm)   Nateglinide (Starlix)
Dipeptidyl peptidase-4 inhibitors Linagliptin (Trajenta)   Saxagliptin (Onglyza)   Sitagliptin (Januvia)   Vildagliptin (Galvus)
Incretin mimetics (GLP-1 agonists and analogs) Exenatide (Byetta)   Liraglutide (Victoza)   Lixisenatide (Lyxumia)   Dulaglutide (Trulicity)
Insulin Sensitizers (drugs that decrease insulin resistance)
Biguanides Metformin (Glucophage)
Thiazolidinediones Pioglitazone (Actos)
Drugs that retard the digestion and absorption of carbohydrates in the small intestine
Alpha-glucosidase inhibitors Acarbose (Glucobay, Precose)
Drugs that reduce glucose absorption in the kidney and increase glucose excretion in the urine
Sodium glucose cotransporter 2 (SGLT2) inhibitors Canagliflozin (Invokana)   Dapagliflozin (Farxiga)   Empagliflozin (Jardiance, Glyxambi, Synjardi)
Insulin and insulin analogs
Intermediate acting insulins Insulin lispro protamine (Humalog BASAL)   Isophane human insulin : Human insulin protamine (NPH) (Humulin I, Protaphane)
Long-acting insulins‎ Insulin detemir (Levemir)   Insulin glargine (Lantus)
Fast-acting insulins‎ Regular insulin : Insulin (Human recombinant) (Actrapid, Humulin R)
Ultra-rapid-acting insulins‎‎ Insulin aspart (Novorapid)   Insulin glulisine (Apidra)   Insulin lispro (Humalog)   Insulin human (Inhalation Powder) (Afrezza)
Premixed insulin‎‎‎ (ultra-rapid-acting + intermediate acting Insulin aspart / Insulin aspart protamine (Novomix)   Insulin lispro / Insulin lispro protamine (Humalog Mix)
Inhaled Insulin Insulin human (Inhalation Powder) (Afrezza)
Combination therapy
Sulfonylurea + Metformin Glibenclamide / Metformin (Bieuglicon M, Diaglimet, Glibomet, Gliconorm, Glicorest, Suguan M)
Thiazolidinedione + Metformin Pioglitazone / Metformin (Competact, Glubrava)
Thiazolidinedione + Sulfonylurea Pioglitazone / Glimepiride (Tandemact)
Dipeptidyl peptidase-4 inhibitors + Metformin Linagliptin / Metformin (Jentadueto)   Sitagliptin / Metformin (Efficib, Janumet, Velmetia)   Vildagliptin / Metformin (Eucreas)