DIABEX

What it is

DIABEX contains metformin hydrochloride. The medicine is available in 500 mg, 850 mg and 1000 mg tablet strengths. Metformin is a biguanide with antihyperglycaemic effects, lowering both basal and postprandial plasma glucose, and does not stimulate insulin secretion and therefore does not cause hypoglycaemia.

Approved indications

— Type 2 diabetes mellitus in adults, children from 10 years of age and adolescents, particularly in overweight patients, when dietary management and exercise alone does not result in adequate glycaemic control. — In adult patients, DIABEX may be used as initial treatment or in sulfonylurea failures either alone or in combination with a sulfonylurea and other oral agents or as adjuvant therapy in insulin requiring type 2 diabetes.

Dosing overview

DIABEX tablets should be taken in divided doses with meals. 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, with the dose titrated with gradual increments until the desired effect is obtained. 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. In children from 10 years of age and adolescents, the usual starting dose is one tablet of 500 mg or 850 mg once daily given during or after meals, with a maximum recommended dose of 2 g daily, taken as two or three divided doses. In elderly patients, the initial and maintenance dosing should be conservative due to the potential for decreased renal function, with any dosage adjustment based on a careful assessment of renal function, and elderly patients should not generally be titrated to the maximum dose.

Key safety warnings

Life threatening lactic acidosis can occur due to accumulation of metformin, with risk factors including renal impairment, old age and the use of high doses of metformin above 2 g per day. Lactic acidosis is a rare but serious metabolic complication with high mortality in the absence of prompt treatment, and reported cases have occurred primarily in diabetic patients with significant renal failure. The risk of lactic acidosis must be considered in the event of non-specific signs such as muscle cramps with digestive disorders such as abdominal pain and severe asthenia, and is characterised by acidotic dyspnea, abdominal pain and hypothermia followed by coma. If metabolic acidosis is suspected, DIABEX should be discontinued, and the patient should be hospitalised immediately. Gastrointestinal disorders such as diarrhoea, nausea, vomiting, abdominal pain and loss of appetite are very common, occur most frequently during initiation of therapy and resolve spontaneously in most cases. To prevent them, it is recommended that DIABEX be taken in 2 or 3 daily doses during or after meals, and a slow increase of the dose may also improve gastrointestinal tolerability. It is recommended that vitamin B12 serum levels are monitored annually, as the risk of low vitamin B12 levels increases with increasing metformin dose, treatment duration, and/or in patients with risk factors known to cause vitamin B12 deficiency.

Contraindications

DIABEX is contraindicated in 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, any type of metabolic acidosis such as lactic acidosis and diabetic ketoacidosis, hypersensitivity to metformin hydrochloride or to any of the excipients, diabetic pre-coma, renal failure or renal dysfunction with creatinine clearance less than 60 mL/min, acute conditions with the potential to alter renal function such as dehydration, severe infection and shock, intravascular administration of iodinated contrast materials, 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 and pancreatitis, elective major surgery, severe hepatic insufficiency, acute alcohol intoxication and alcoholism. DIABEX is also contraindicated during lactation.

PBS listing

Information regarding PBS listing details including item number, restriction type and ex-manufacturer price is not provided in the available source documents.

Regulatory history

DIABEX metformin hydrochloride tablets were first registered on the ARTG on 13 August 1992 in the 500 mg strength, followed by the 850 mg strength on 25 October 1996 and the 1000 mg strength on 17 June 2002.