Metformin Teva B.V. (Metformin Hydrochloride)

Metformin is an oral antidiabetic agent that acts on glucose metabolism in type 2 diabetes mellitus.

• Type 2 diabetes mellitus: lowers fasting plasma glucose and HbA1c levels, improving overall glycemic control.
• Type 2 diabetes mellitus: reduces hepatic glucose production, helping to control post‑prandial glucose excursions.
• Type 2 diabetes mellitus: enhances peripheral insulin sensitivity, contributing to better glucose utilization.

• Metformin exerts its antihyperglycaemic effect primarily by inhibiting mitochondrial respiratory‑chain complex I, which decreases hepatic gluconeogenesis. The resulting reduction in hepatic glucose output, together with activation of AMP‑activated protein kinase, improves insulin‑mediated glucose uptake in muscle and adipose tissue, thereby lowering circulating blood glucose concentrations. Metformin also modestly decreases intestinal glucose absorption and may influence gut microbiota composition, contributing further to its glucose‑lowering actions.

Metformin may cause a range of adverse reactions, most of which are related to the gastrointestinal tract, while rare but serious events can also occur.

Common Side Effects

• Nausea: mild to moderate nausea, especially at therapy initiation.
• Diarrhea: loose stools that may be transient.
• Abdominal discomfort: cramping or bloating.
• Metallic taste: transient metallic sensation in the mouth.

Serious or Rare Side Effects

• Lactic acidosis: life‑threatening accumulation of lactate, particularly in renal impairment.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Hepatic failure: rare liver injury.
• Hypoglycemia: when combined with insulin or secretagogues.

When prescribing Metformin, several safety considerations should be evaluated to minimize risk.

• Renal function: assess eGFR before initiating and monitor periodically.
• Hepatic function: avoid use in patients with severe liver disease.
• Lactic acidosis risk: contraindicated in conditions predisposing to hypoxia such as heart failure or severe infection.
• Pregnancy: category B; use only if potential benefit justifies the potential risk.
• Vitamin B12 monitoring: long‑term therapy may reduce B12 levels; periodic assessment recommended.
• Store at ambient temperature: keep below 25°C, protect from moisture and light.

Metformin can interact with several medicines, affecting its plasma concentration or increasing the risk of adverse effects.

Major Interactions (Avoid)

• Iodinated contrast agents: may cause acute kidney injury; hold Metformin before and after the procedure.
• Cimetidine: can increase Metformin plasma levels, raising the risk of toxicity.
• Alcohol abuse: potentiates the risk of lactic acidosis.

Moderate Interactions (Monitor Closely)

• Beta‑blockers: may mask symptoms of hypoglycemia.
• Diuretics (loop or thiazide): can affect renal clearance of Metformin.
• ACE inhibitors or ARBs: may influence renal function, requiring monitoring.