Iruka (Metformin Hydrochloride)

Metformin is an oral antidiabetic that acts on glucose metabolism in type 2 diabetes and related insulin‑resistant conditions.

• Type 2 diabetes mellitus: lowers fasting and post‑prandial blood glucose levels.
• Prediabetes (impaired glucose tolerance): helps delay progression to overt diabetes.
• Polycystic ovary syndrome (PCOS): improves insulin sensitivity and may regularise menstrual cycles.

• Metformin reduces hepatic gluconeogenesis and increases peripheral glucose uptake by activating AMP‑activated protein kinase (AMPK). This leads to decreased liver glucose output and enhanced insulin‑mediated glucose utilization in muscle and adipose tissue, resulting in lower plasma glucose concentrations without stimulating insulin secretion.

Metformin is generally well tolerated, but a range of adverse reactions have been reported.

Common Side Effects

• Gastrointestinal upset: nausea, abdominal discomfort, and loss of appetite.
• Diarrhea: frequent loose stools, especially during treatment initiation.
• Metallic taste: transient alteration of taste perception.
• Vitamin B12 deficiency: gradual reduction in serum B12 levels with long‑term use.

Serious or Rare Side Effects

• Lactic acidosis: a rare but life‑threatening accumulation of lactate.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Hepatic dysfunction: marked elevation of liver enzymes or hepatitis.

Metformin requires careful monitoring in several clinical situations.

• Renal function: assess creatinine clearance before initiation and periodically thereafter.
• Hepatic function: evaluate liver enzymes as impaired liver may increase lactic acidosis risk.
• Heart failure: avoid in decompensated heart failure due to reduced perfusion.
• Vitamin B12 status: monitor levels during long‑term therapy.
• Pregnancy and lactation: use only if clearly needed after risk‑benefit assessment.
• Store at room temperature: keep in the original container, protect from moisture and heat.

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

Major Interactions (Avoid)

• Alcohol: potentiates risk of lactic acidosis.
• Iodinated contrast agents: can cause acute renal impairment, increasing metformin exposure.
• Cimetidine: may raise plasma metformin concentrations.

Moderate Interactions (Monitor Closely)

• Sulfonylureas: additive hypoglycaemic effect, monitor blood glucose.
• Beta‑blockers: may mask hypoglycaemia symptoms.
• Diuretics (especially thiazides): can affect renal clearance of metformin.
• ACE inhibitors/ARBs: monitor renal function when combined.