Metformin Zentiva (Metformin Hydrochloride)

Metformin, a biguanide antidiabetic agent, is used to improve glycaemic control in type 2 diabetes mellitus.

• Type 2 diabetes mellitus: lowers fasting and post‑prandial blood glucose levels, aiding overall glycaemic management.
• Prediabetes (impaired glucose tolerance): helps delay progression to overt type 2 diabetes when combined with lifestyle changes.
• Polycystic ovary syndrome (off‑label): may improve insulin resistance and menstrual regularity in affected women.
• Metabolic syndrome: contributes to weight management and enhanced insulin sensitivity as part of a comprehensive treatment plan.
• Combination therapy with insulin: reduces the required insulin dose while maintaining target glucose levels.

• Metformin exerts its antihyperglycaemic effect primarily by inhibiting hepatic gluconeogenesis, thereby decreasing endogenous glucose production. It also enhances peripheral glucose uptake by increasing insulin‑mediated activation of AMP‑activated protein kinase (AMPK) in muscle and adipose tissue, which improves insulin sensitivity and reduces intestinal glucose absorption.

Metformin may be associated with a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea: mild stomach upset, often transient.
• Diarrhea: loose stools, usually early in treatment.
• Abdominal discomfort: cramping or pain in the upper abdomen.
• Metallic taste: temporary alteration in taste perception.

Serious or Rare Side Effects

• Lactic acidosis: rare but potentially fatal accumulation of lactate, requiring urgent care.
• Severe hypoglycaemia: especially when used with insulin or sulfonylureas.
• Hepatic dysfunction: signs of liver injury such as jaundice or elevated enzymes.

When prescribing Metformin, several precautions should be observed to minimise risk and ensure safe use.

• Renal function assessment: evaluate eGFR before initiation and periodically during therapy.
• Lactic acidosis risk: avoid in patients with severe renal or hepatic impairment, or conditions predisposing to hypoxia.
• Alcohol consumption: limit intake to reduce the risk of lactic acidosis.
• Vitamin B12 monitoring: consider periodic testing during long‑term treatment.
• Pregnancy and lactation: discuss potential risks with a healthcare professional before use.
• Store at ambient temperature: keep in the original container, protect from moisture and heat.

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

Major Interactions (Avoid)

• Iodinated contrast media: can precipitate acute renal failure, increasing metformin accumulation.
• Cimetidine: raises metformin plasma concentrations, heightening risk of adverse effects.
• Nitrates: may potentiate the rare occurrence of lactic acidosis.

Moderate Interactions (Monitor Closely)

• Beta‑blockers: may mask symptoms of hypoglycaemia.
• Thiazide diuretics: can attenuate glucose‑lowering effect of metformin.
• ACE inhibitors or ARBs: require monitoring of renal function and electrolytes.