Full Prescribing Info
Metformin hydrochloride.
Each tablet contains: Metformin hydrochloride 500 mg.
Pharmacology: Pharmacodynamics: Metformin acts primarily by reducing hepatic glucose production and increasing peripheral glucose uptake. Insulin production is not affected and so hypoglycemia as a side effect does not occur. Metformin does not cause weight gain and so is the treatment of choice for obese patients. Metformin HCl is equally effective in the non-obese. It induces comparable effects on fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA) levels to the sulfonylureas. Metformin HCl has a favorable effect on plasma lipids and the homeostatic mechanism.
Metformin HCl does not stimulate insulin release but does require that some insulin be present for it to exert a hypoglycemic effect. Possible mechanisms of action include delay in the absorption of glucose from the gastrointestinal tract, an increased in insulin sensitivity and inhibition of hepatic gluconeogenesis. Metformin HCl does not usually lower blood-glucose concentrations in non-diabetic patients.
Pharmacokinetics: Absorption and Fate: Metformin hydrochloride is absorbed from the gastro-intestinal tract. It has a plasma half-life of about 3 hours and is not bound to plasma proteins. Metformin HCl is excreted unchanged in the urine. Its hypoglycemic action lasts 6-8 hours.
Metformin is biguanide hypoglycaemia agent used in the treatment of non-insulin-dependent diabetes mellitus (NIDDM) not responding to dietary modification. It is used as a monotherapy or in combination with a sulfonylurea product. In Type 1 diabetic patients or insulin deficient patients, who are not adequately controlled, metformin may be combined with insulin.
Dosage/Direction for Use
Initial dose of 500 mg three times daily with or after meals, gradually increased if necessary to a maximum of 3 g daily.
Metformin HCL is contraindicated in renal impairment and liver failure because of an increased risk of hypoglycemia. Renal impairment may also predispose patients to lactic acidosis. Regular renal and hepatic monitoring is essential.
Metformin HCl should also not be given to patients with heart failure, recent myocardial infarction, dehydration, alcoholism or any other condition likely to predispose to lactic acidosis.
Use In Pregnancy & Lactation
Use of metformin HCl is not recommended.
Adverse Reactions
Gastrointestinal adverse effects including anorexia, nausea and diarrhea may occur and is dose dependent. These effects can be limited by administering with food and starting with low dose (500 mg once or twice a day), then slowly titrating the dose upwards according to the clinical response.
Patients may experience a metallic taste and there may be weight loss. Absorption of various substances including vitamin B12 may be impaired. Hypoglycemia is less of a problem with metformin than with the sulfonylureas.
Lactic acidosis is rare and occurs predominantly in patients with renal impairment.
Drug Interactions
Drug interactions involve drugs also excreted by the renal tubular pathway (e.g. amiloride, cimetidine, digoxin, morphine, procainamide, quinidine, vancomycin, trimethoprim). Cimetidine may increase metformin levels by up to 50%.
Store at temperatures not exceeding 30°C.
MIMS Class
ATC Classification
A10BA02 - metformin ; Belongs to the class of biguanides. Used in the treatment of diabetes.
FC tab 500 mg x 60's.
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