Metformin is a biguanide oral anithyperglycemic agent. It is structurally related to guanidine, which is the active substance contained in French lilac (Galega officinalis), a traditional remedy for diabetes.
Pharmacology: Metformin reduces elevated blood glucose levels, predominantly by improving hepatic and peripheral tissue sensitivity to insulin without affecting secretion of this hormone. It also increases glucose utilization and reduces glucose production. Metformin has potentially beneficial effects on serum lipid profiles. Reduced circulating levels of free fatty acids, triglycerides and LDL cholesterol and increased HDL cholesterol levels have been reported in particular.
Pharmacokinetics: Metformin has on oral bioavailability of 50-60%, and GI absorption is apparently complete within 6 hrs of ingestion. It is rapidly distributed and does not bind to plasma proteins. No metabolites have been identified. The drug undergoes renal excretion and has a plasma elimination t½ after oral administration of between 4 and 8.7 hrs. This is prolonged in patients with renal impairment and correlates with CrCl.
Management of diet-failed, non-insulin dependent diabetes mellitus (NIDDM), especially if overweight or attempts to achieve acceptable control with sulfonylurea therapy and physical activity have failed. Since it also promotes weight loss, it is particularly useful in obese patients.
Initial dose: 500-1000 mg daily, in divided doses with or without meals. Maximum dose: Five 500-mg tablets daily.
Juvenile DM; coma diabeticum ketosis; renal and hepatic insufficiency; cardiac or respiratory insufficiency; severe infection; very old patients; alcohol abuse; history of lactic acidosis; pregnancy; 2 days before and after IV administration of x-ray contrast medium; before, during or after surgery; hypersensitivity to metformin.
Check for renal and hepatic competence and postprandial lactate during usage, caution with concomitant cimetidine therapy.
Contraindicated during pregnancy.
Lactic acidosis is the biguanide related adverse effect of most concern, although serious, it is rare and may be minimized by strict adherence to contraindications. Acute reversible adverse effect are mainly of GI origin (discomfort, diarrhea, nausea, anorexia) and may be minimized by taking the drug with or after meals.
It may impair absorption of vitamin B12
and folic acid.
Concomitant administration of drugs with own plasma glucose-lowering potential, eg, oral antihyperglycemic, salicylates and pyrazolones, MAOIs, oxytetracycline, ACE inhibitors, derivatives of clofibrate, cyclophosphamide and insulin may cause hypoglycemia.
Beta blockers and sympatholytic drugs like clonidine, reserpine and guanethidine may induce plasma glucose-lowering effects during long-term administration.
The glucose-lowering effect of metformin may be decreased due to concomitant administration of glucocorticoids, oral contraceptives, adrenaline and other sympathomimetics, glucagons, thyroid hormones and phenothiazines. Cimetidine diminishes renal elimination of metformin and concomitant use may produce lactic acidosis.
Concomitant acute and chronic abuse of alcohol may elevate hypoglycemic activity of metformin and production of lactic acid.
Store at temperatures not exceeding 30°C.
A10BA02 - metformin ; Belongs to the class of biguanides. Used in the treatment of diabetes.
Neomet tab 500 mg