Mechanism of action of metformin,most widely used anti hyperglycaemic drug.

[patliputra]

Metformin is a hypoglycemic drug effective in the treatment of non-insulin-dependent diabetes mellitus and increasingly used in Canada and Europe. Effects on intestinal glucose absorption, insulin secretion, and hepatic glucose production are insufficient to explain its hypoglycemic action, with most evidence suggesting that the major effect of the drug is on glucose utilization. In vivo and in vitro studies have demonstrated that metformin stimulates the insulininduced component of glucose uptake into skeletal muscle and adipocytes in both diabetic individuals and animal models. This increase is more significant in diabetic than in nondiabetic animals, suggesting an enhanced action of the drug in the hyperglycemic state. The increase in glucose uptake is also reflected in an increase in the insulin-dependent portion of glucose oxidation. Potential sites of action of metformin are the insulin receptor and the glucose transporters. Although metformin increases insulin binding in various cell types, this effect is not universal and does not correlate with stimulation of glucose utilization. In contrast, direct effects of the drug on the glucose-transport system have been demonstrated. Metformin elevates the uptake of nonmetabolizable analogues of glucose in both nondiabetic rat adipocytes and diabetic mouse muscle. In the latter, the stimulatory effect of the drug is additive to that of insulin. In human and rat muscle cells in culture, metformin increases glucose-analogue transport independently of and additive to insulin, suggesting an insulin-independent action. Most of these results suggest that the basis for the hypoglycemic effect of this biguanide is probably at the level of skeletal muscle by increasing glucose transport across the cell membrane.

In nut shell the pharmacological mechanism of action are different from other classes of oral anti hyperglycaemic agents. Metformin decreases hepatic glucose production,decrease intestinal absorption of glucose and improve insulin sensitivity,increasing peripheral glucose uptake and utilisation.

rxlist.com>clinical-pharmac... 

care.diabetesjournals.org

[patliputra]

If you have latest information please update and enlighten.

[patliputra]

It's okay. But not sufficient. I have posted the latest non technical information on metformin. If you find something more to add  please share.

[Hidden]

Unfortunately, Metformin have unpleasant side effects, Patliputra - it causes hair drop for a start. That happened to me and many others who have taken it, esp. those women who have polycystic ovary syndrome.  Secondly, it acidifies the blood and it can cause lactic acidosis, a serious problem requiring emergency attention.  Thirdly, it causes GI distress. Fourthly, it loses efficacy over time and you end up increasing the dosage until you max it at 6 x 500 mg a day.  By then, your body will suffer from increasing acidity and this is detrimental to blood circulation, etc. 

Up to this day, how Metformin works is still a conjectural affair - good, educated guesses at best.  There is one good candidate or factor that is seldom talked about - I'll try to write a post on this one day.

[patliputra]

Side effects are far and few. Gastric irritation do occur sometimes but that is also not common. Lactic acidosis is rare phenomenon. As a matter of fact all allopathic medicines carry one or another side effect.

Metformin is supposed to be the safest anti hyperglycemic drug.

[patliputra]

Effective on both fasting and pp blood sugar.

[jan-ran]

arunkumar, Could you explain 'SR' please?

[shrisamarth Volunteer in reply to jan-ran]

Sustained Release.

[jan-ran]

Thank you shrisamarth