Endocrinology Book

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GlucophageAka: Metformin, Biguanide

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  1. See Also
    1. Oral Hypoglycemic Agents
  2. Mechanism
    1. Lower risk for Hypoglycemia
    2. Inhibits gluconeogenesis
  3. History
    1. Other Biguanides removed from U.S. market in 1960's
      1. Toxicity limited prior use
    2. Oldest Diabetes Mellitus agent
      1. Derivative of Goat's Rue (French Lily)
      2. Used in medieval Europe for Diabetes Mellitus
  4. Pathophysiology
    1. Decreases hepatic glucose production
    2. Increases peripheral glucose uptake
    3. Slows intestinal glucose absorption
  5. Indications
    1. First line agent in Type II Diabetes Mellitus
      1. Obese patients
      2. Hyperlipidemia
      3. Children over age 10 with Type II Diabetes
    2. Metabolic Syndrome
    3. Polycystic Ovary Syndrome (PCOS)
    4. Induces Ovulation (with or without Hyperandrogenism)
      1. Carmina (2004) Am J Obstet Gynecol 191:1580
    5. Other indicators
      1. Hemoglobin A1C <9%
      2. High fasting Blood Glucose 160-250 mg/dl
      3. Dyslipidemia
  6. Contraindications
    1. Risk of Lactic Acidosis
      1. Avoid in Renal Insufficiency (GFR <60 ml/min)
        1. Serum Creatinine >1.5 in men and >1.4 in women
      2. Avoid with Alcohol Abuse
      3. Avoid concurrent IV iodinated contrast dye use
        1. Allow 48 hour wash-out of dye or
        2. Confirm normal Renal Function tests after dye
    2. Avoid in hepatic insufficiency
      1. Also avoid if excessive Alcohol
    3. Hold prior to iodinated contrast dye or surgery
    4. Avoid in Proteinuria
    5. Avoid in Peripheral Vascular Disease
    6. Avoid in Coronary Artery Disease
    7. Not contraindicated in stable Congestive Heart Failure
      1. Eurich (2007) BMJ 335(7618):497
  7. Dosing: General
    1. Maximum daily dose of Metformin is 2500 mg (for either regular or XR)
    2. Effective maximum dose is 2000 mg daily
      1. Effect drops off above 2000 mg
    3. Dose related drop in fasting Blood Glucose
      1. Metformin 500 mg decreases fasting Blood Glucose by 19 mg/dl
      2. Metformin 1000 mg decreases fasting Blood Glucose by 31 mg/dl
      3. Metformin 1500 mg decreases fasting Blood Glucose by 41 mg/dl
      4. Metformin 2000 mg decreases fasting Blood Glucose by 78 mg/dl
      5. Metformin 2500 mg decreases fasting Blood Glucose by 62 mg/dl
    4. References
      1. Garber (1997) :
  8. Dosing: Short acting
    1. Week 1: 500 mg PO bid
    2. Week 2
      1. Example 1: 1000 mg PO qAM and 500 mg PO qPM
      2. Example 2: 850 mg PO bid
    3. Week 3: 1000 mg PO bid
  9. Dosing: Long Acting
    1. Start: Metformin XR 500 mg daily
    2. Increase by 500 mg weekly until at 2000 mg or at goal blood sugar
  10. Cost
    1. More expensive than Sulfonylureas (except generic metformin)
    2. Less expensive than Thiazolidinediones
  11. Adverse effects
    1. Lactic Acidosis Risk
      1. See contraindications above
    2. Abdominal discomfort
    3. Diarrhea
    4. Metallic Taste
    5. Nausea or Vomiting
    6. Anorexia
    7. Decreased absorption of Vitamin B12
    8. Decreased absorption of Folic Acid
  12. References
    1. Bailey (1996) N Engl J Med 334:574
    2. Defronzo (1995) N Engl J Med 333:541
    3. Hermann (1994) Diabetes Care 17:1100
    4. Stumvoll (1995) N Engl J Med 333:550
    5. Luna (2001) Am Fam Physician 63(9):1747

Biguanides (C0005382)

ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
EnglishBiguanide, Biguanides
Spanishbiguanida
CreditsDerived from the NIH UMLS (Unified Medical Language System)


Metformin (C0025598)

Definition (MSH)A biguanide hypoglycemic agent used in the treatment of non-insulin-dependent diabetes mellitus not responding to dietary modification. Metformin improves glycemic control by improving insulin sensitivity and decreasing intestinal absorption of glucose. (From Martindale, The Extra Pharmacopoeia, 30th ed, p289)
Definition (NCI)A biguanide with antihyperglycemic activity. Metformin hydrochloride exerts its action by improving hepatic sensitivity to insulin, thereby suppressing hepatic glucose production and increasing hepatic glycogen stores. In addition, metformin hydrochloride increases the number and/or affinity of insulin receptors on cell surface membranes in muscle and adipose tissue, thereby increasing the sensitivity to insulin at receptor and post-receptor binding sites and increasing glucose uptake peripherally.
Definition (CSP)N,N-dimethylimidodicarbonimidic diamide; an oral hypogylcemic agent.
ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
EnglishDimethylbiguanidine, Dimethylguanylguanidine, Metformin, METFORMIN PREPARATION
Spanishmetformina
CreditsDerived from the NIH UMLS (Unified Medical Language System)


Glucophage (C0591573)

ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
EnglishGlucophage
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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