Glucophage (Metformin Hydrochloride)

Glucophage is indicated for the treatment of type 2 diabetes mellitus, primarily to improve glycemic control when diet and exercise alone are insufficient.

• As monotherapy in patients newly diagnosed with type 2 diabetes.
• In combination with other oral antidiabetic agents (e.g., sulfonylureas, DPP‑4 inhibitors) when additional glucose lowering is needed.
• As adjunct to insulin therapy to reduce insulin dose requirements.
• For patients with overweight or obesity to aid weight management while controlling blood glucose.
• Occasionally used off‑label for polycystic ovary syndrome under specialist supervision.

The safety profile of metformin includes both frequently reported and less common adverse events.

Common

• Nausea, abdominal discomfort, diarrhea, and occasional constipation, typically occurring during the initial weeks of therapy and often improving with dose titration.
• A metallic or bitter taste in the mouth, which is generally transient.
• Decreased absorption of vitamin B12 over prolonged treatment, which may lead to mild anemia if not monitored.

Serious

• Lactic acidosis, a rare but life‑threatening condition characterized by elevated blood lactate levels, especially in patients with renal impairment or hypoxia.
• Severe cutaneous adverse reactions such as Stevens‑Johnson syndrome or toxic epidermal necrolysis, requiring immediate medical attention.
• Hepatic dysfunction or acute renal failure that can result from metformin accumulation, necessitating prompt discontinuation.

Before initiating Glucophage, clinicians should evaluate several clinical factors to minimize risk and ensure appropriate use.

• Assess renal function; metformin is contraindicated in severe renal impairment (eGFR <30 mL/min/1.73 m²).
• Review hepatic status, as liver disease may increase the risk of lactic acidosis.
• Evaluate for conditions that predispose to hypoxia (e.g., heart failure, recent myocardial infarction, respiratory disease).
• Consider age and frailty; older adults may require lower starting doses.
• Monitor vitamin B12 levels periodically during long‑term therapy.
• Advise patients to temporarily discontinue metformin before any radiographic studies using iodinated contrast agents.

Metformin may interact with other medicines, affecting its efficacy or safety.

Avoid

• Iodinated contrast agents for imaging studies; they can precipitate acute kidney injury and increase lactic acidosis risk.
• Cimetidine, as it can reduce metformin clearance and raise plasma concentrations.

Use with caution

• Alcohol, which may potentiate lactic acidosis, especially in excess.
• Diuretics and ACE inhibitors, which can affect renal function and require monitoring of kidney parameters.
• Other antidiabetic agents (e.g., sulfonylureas, insulin) to avoid hypoglycemia when combined.