Glucophage

Glucophage contains metformin hydrochloride, the most widely prescribed first-line oral medication for the management of type 2 diabetes mellitus.

It belongs to the biguanide class and is recommended when blood glucose is not adequately controlled by diet, exercise, and lifestyle modification alone.

Metformin works through multiple mechanisms. Its primary action is to reduce hepatic glucose output by suppressing gluconeogenesis.

It also enhances insulin sensitivity in peripheral tissues, particularly skeletal muscle, increasing glucose uptake and utilisation. Additionally, metformin delays intestinal absorption of glucose.

Importantly, it does not stimulate insulin secretion from the pancreas and therefore does not cause hypoglycaemia when used as monotherapy.

Glucophage is available as standard-release and prolonged-release tablets.

It may be prescribed as monotherapy or in combination with other antidiabetic agents, including sulfonylureas, DPP-4 inhibitors, SGLT2 inhibitors, GLP-1 receptor agonists, or insulin.

Metformin has a neutral to slightly beneficial effect on body weight, which is an advantage over many other diabetes treatments.

Take Glucophage with or immediately after meals to minimise gastrointestinal side effects. Swallow the tablets whole with water.

Do not crush or chew prolonged-release tablets; they must be swallowed intact to maintain the modified-release mechanism.

Your doctor will start at a low dose and increase gradually over several weeks to improve tolerability.

Monitor your blood glucose as directed by your healthcare team.

Continue taking Glucophage even when you feel well, as type 2 diabetes often produces no immediate symptoms despite causing long-term damage at elevated glucose levels.

Standard-release: start at 500 mg once or twice daily with meals, increasing by 500 mg every one to two weeks.

The usual maintenance dose is 500 mg to 1,000 mg two or three times daily, up to a maximum of 3,000 mg per day.

Prolonged-release: start at 500 mg once daily with the evening meal, increasing by 500 mg every one to two weeks, up to a maximum of 2,000 mg once daily.

In moderate renal impairment (eGFR 30-45), the maximum dose is 1,000 mg daily, with regular eGFR monitoring. Metformin must not be used if eGFR falls below 30.

Common side effects (more than 1 in 10 patients) include nausea, vomiting, diarrhoea, abdominal pain, and loss of appetite.

These symptoms are most pronounced when starting treatment and during dose increases, and usually improve within a few weeks. A metallic taste in the mouth is also frequently reported.

Uncommon effects include skin rash and pruritus.

Long-term use may reduce vitamin B12 absorption, potentially leading to deficiency, which can cause peripheral neuropathy and megaloblastic anaemia if undetected.

The most serious adverse effect is lactic acidosis, which is very rare but carries a high mortality rate.

Risk factors include severe renal impairment, dehydration, excessive alcohol intake, hepatic insufficiency, and conditions causing tissue hypoxia (such as acute heart failure or sepsis).

Symptoms include rapid breathing, abdominal pain, muscle cramps, hypothermia, and general malaise. Seek emergency medical attention if these develop.

Metformin should be temporarily discontinued before procedures using iodinated contrast media, during acute illness causing dehydration or haemodynamic instability, and for 48 hours after surgery under general anaesthesia.

Renal function (eGFR) should be checked at least annually, and more frequently in patients with declining function or additional risk factors.

Limit alcohol intake, as alcohol increases the risk of lactic acidosis. Monitor vitamin B12 levels periodically, particularly if peripheral neuropathy symptoms develop.

Glucophage is contraindicated in patients with severe renal impairment (eGFR below 30 mL/min), diabetic ketoacidosis, diabetic pre-coma, acute conditions with potential to alter renal function (dehydration, severe infection, shock), acute or chronic disease that may cause tissue hypoxia (heart failure, respiratory failure, recent myocardial infarction), hepatic insufficiency, acute alcohol intoxication, and alcoholism.

It is not suitable for type 1 diabetes.