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Clinician’s Corner: METFORMIN—every Type-2 diabetic should be taking this drug!

Another plant is the source of a very common diabetes drug from the French lilac or goat’s rue.  The medicinal value of this plant in lowering blood sugars was discovered in the 1700’s but it wasn’t until 1995 that this drug became available in the United States as Metformin “Glucophage®”.

METFORMIN—every Type-2 diabetic should be taking this drug!

How it works:

  • Decreases glucose production in the liver & improves insulin sensitivity
  • Major effects occur in the liver to decrease glucose output, and to a lesser extent, by increasing glucose utilization in the body.  Figure this drug works about 80% in the liver and 20% in the periphery.


  • Reduction in HgBAc1: (1.5%)
  • Reduction in Fasting plasma glucose: 50-70 mg/dl

Target population: overweight, insulin resistant and children (approved for patients over age -10)

DOSE: Start low and go slow to avoid gastrointestinal upset.

  • initial: 500 twice daily or 850 daily (XR=500mg at supper)
  • usual: 1000mg twice daily or 850 three times daily maximum dose=2550mg/day   (XR=1500-2000 at supper)
  • COST: both immediate release and extended release are available generically are inexpensive. Wide formulary coverage.

CAUTION:  Metformin XR 1000mg is ridiculously expensive.  The cheapest generic formula for Metformin ER 1000mg is nearly $900.00 for 60 tablets.  Valeant Pharmaceuticals makes a generic that the wholesale acquisition is $6,000 for 60 tablets.  We can fill 120 generic Metformin XR-500mg for less than $20.00!! Have your Thompson Pharmacist call your doctor’s office to make this change.  We want to save you money and keep you out of the donut hole!!

Metformin should be prescribed at the first office visit when the diagnosis of Type-2 diabetes is made. Metformin can be used by itself or in combination with other diabetes drugs.

Patient Information:

  • Watch for Lactic Acidosis (rare – 3/100,000 patient years). Here are signs and symptoms:
    • feeling very weak, tired or uncomfortable
    • unusual muscle pain or cramps
    • trouble breathing
    • unusual or unexpected stomachache, decreased appetite or diarrhea
    • feeling cold, dizzy or light-headed
    • developing an irregular heartbeat
  • Avoid metformin if serum creatinine is over 1.5 in males or over 1.4 in females.
  • Caution if alcohol abuse & liver disease.
  • Metformin medications should be stopped at the time of or prior to CT studies with IV Contrast and withheld for 48 hours after the procedure.
  • Stop if kidney function falls below than 30 ml/minute
  • Take with food to minimize stomach upset. Dose should be increased gradually to decrease side effects such as metallic taste, diarrhea, nausea, abdominal pain
  • HEART FAILURE: Metformin is safe for heart patients. It is protective, because it causes weight loss.

WATCH for Metformin induced Vitamin B12 deficiency   

  • Up to 30% of patients on metformin have reduced B12 absorption which could eventually lead to B12 deficiency. Besides ANEMIA, Vit-B12 deficiency can cause peripheral nerve damage, which can be mistaken for Diabetic Peripheral Neuropathy (DPN). I have treated four men who were taking metformin who had tingling in their hands, and Vitamin B-12 stopped the tingling.
  • Treatment: B-12 injections are usually not necessary, oral B12 (1000mcg PO daily) is enough.  Don’t stop metformin, just treat the B12 deficiency.  Consult your Thompson Pharmacist!

Nearly 327 BILLION dollars will be spent this year to manage diabetes in the United States.   Your Thompson Pharmacist is a great resource to help you manage your diabetes and save you money.  Diet and exercise are extremely important along with medications to manage your diabetes.  You do the diet and exercise; we’ll do the medications.  Go AHEAD and ask… at Thompson Pharmacy it’s all for YOU!!