Metformin Teva B.V. (Metformin Hydrochloride)

• Metformin is indicated for conditions affecting glucose metabolism and insulin sensitivity.
• Type 2 diabetes mellitus: improves glycemic control by lowering fasting and post‑prandial blood glucose levels.
• Prediabetes (impaired fasting glucose): delays progression to overt diabetes when used with lifestyle measures.
• Polycystic ovary syndrome (off‑label): reduces insulin resistance and may help restore regular menstrual cycles.

• Metformin decreases hepatic gluconeogenesis, reduces intestinal glucose absorption, and enhances peripheral insulin sensitivity by activating AMP‑activated protein kinase (AMPK). This combined action lowers circulating glucose without stimulating insulin secretion, helping to maintain stable blood‑sugar levels in patients with type 2 diabetes.

Metformin is generally well tolerated, but several adverse reactions have been reported.

Common Side Effects

• Nausea or upset stomach
• Diarrhea or loose stools
• Abdominal discomfort or cramping
• Metallic taste in the mouth
• Decreased appetite
• Mild weight loss

Serious or Rare Side Effects

• Lactic acidosis, a potentially life‑threatening metabolic disturbance
• Severe skin reactions such as Stevens‑Johnson syndrome
• Hepatic failure or significant liver enzyme elevation
• Marked hypoglycemia when combined with insulin or sulfonylureas
• Vitamin B12 deficiency with long‑term use

• Metformin requires careful assessment of patient factors and monitoring.
• Renal function assessment: evaluate eGFR before initiating and periodically during therapy.
• Lactic acidosis risk: avoid in patients with severe renal or hepatic impairment.
• Pregnancy safety: Category B; use only if potential benefits justify the risk.
• Alcohol consumption: limit intake as it may increase lactic acidosis risk.
• Drug interaction review: assess concomitant medicines that affect renal clearance or glucose levels.
• Store at ambient temperature: keep below 25 °C, in the original container, protected from moisture and direct sunlight.

Metformin may interact with several medicines, requiring vigilance.

Major Interactions (Avoid)

• Iodinated contrast agents: can precipitate acute renal failure and lactic acidosis.
• Cimetidine: may increase metformin plasma concentrations.
• Alcohol excess: heightens risk of lactic acidosis.
• Nephrotoxic drugs (e.g., aminoglycosides, NSAIDs): can impair renal clearance of metformin.
• High‑dose vitamin B12 supplements: may mask deficiency symptoms.

Moderate Interactions (Monitor Closely)

• Sulfonylureas or insulin: increased risk of hypoglycemia.
• Beta‑blockers: may blunt hypoglycemia warning signs.
• Thiazide diuretics: can attenuate glucose‑lowering effect.
• ACE inhibitors or ARBs: monitor renal function and potassium levels.
• Oral contraceptives: may slightly raise metformin levels.