FORMET

What it is

FORMET contains metformin hydrochloride. FORMET tablets come in four strengths: FORMET 250 contains 250 mg metformin hydrochloride, FORMET 500 contains 500 mg metformin hydrochloride, FORMET 850 contains 850 mg metformin hydrochloride, and FORMET 1000 contains 1000 mg metformin hydrochloride. Metformin is a biguanide with antihyperglycaemic effects on both basal and postprandial hyperglycaemia.

Approved indications

— Type 2 diabetes mellitus not satisfactorily controlled by diet, where the risk of lactic acidosis is minimised by excluding predisposing factors, especially impaired renal, hepatic or cardiovascular function. Metformin may be used as initial therapy or in sulphonylurea failure, either alone or in combination with a sulphonylurea or as adjuvant therapy in insulin-dependent diabetes.

Dosing overview

Initially 500 mg should be taken once or twice a day and, if necessary, increased over a few weeks up to 1 g three times per day. 500 mg three times a day is often sufficient to obtain diabetic control. If necessary, the dose can be increased to 1 g three times daily, which is the maximum recommended daily dose. The tablets should be taken in divided doses with meals. Once control has been obtained, the dosage should be reviewed and reduced to the lowest maintenance level consistent with good diabetic control.

Key safety warnings

Life threatening lactic acidosis can occur due to accumulation of metformin. Risk factors include renal impairment, old age and the use of high doses of metformin above 2 g per day. Lactic acidosis is a rare but serious (high mortality in the absence of prompt treatment), metabolic complication that can occur due to metformin accumulation. Reported cases of lactic acidosis in patients on metformin have occurred primarily in diabetic patients with significant renal failure. In patients with known mitochondrial diseases such as Mitochondrial Encephalopathy with Lactic Acidosis, and Stroke-like episodes (MELAS) syndrome and Maternal inherited diabetes and deafness (MIDD), metformin is not recommended due to the risk of lactic acidosis exacerbation and neurologic complications which may lead to worsening of the disease. Metformin induces a reduction in thyrotropin (thyroid stimulating hormone (TSH)) levels in patients with treated or untreated hypothyroidism. Regular monitoring of TSH levels is recommended in patients with hypothyroidism. Studies have shown that metformin reduces plasma TSH levels, often to subnormal levels, when it is administered to patients with untreated hypothyroidism or to hypothyroid patients effectively treated with Levothyroxine.

Contraindications

Juvenile diabetes mellitus that is uncomplicated and well regulated on insulin; diabetes mellitus regulated by diet alone; during or immediately following surgery where insulin is essential; hypersensitivity to metformin hydrochloride or to any of the excipients; any type of metabolic acidosis (such as lactic acidosis, diabetic ketoacidosis); diabetic pre-coma; renal failure or renal dysfunction (creatinine clearance <60 mL/minute); acute conditions with the potential to alter renal function such as dehydration, severe infection, shock; intravascular administration of iodinated contrast material; acute or chronic disease which may cause tissue hypoxia such as cardiac failure, recent myocardial infarction, respiratory failure, pulmonary embolism, shock, acute significant blood loss, sepsis, gangrene; pancreatitis; elective major surgery; severe hepatic insufficiency; acute alcohol intoxication; alcoholism; lactation.

Regulatory history

FORMET 250, 500, 850 and 1000 were first listed on the ARTG on 31 October 2002. The product information was last revised on 23 March 2026.