Metformin

Hypoglycaemic excluding Insulin · Biguanide

Indications

Maturity-onset diabetes either alone or with sulphonylureas. Adjuvant therapy in insulin-dependent diabetes, particularly in the obese.

Dosage

Adults: Initial 500 mg twice daily or 850 mg daily with meals. Titrate: Increase by 500 mg every wk, or 850 mg every two wk, or from 500 mg twice daily to 850 mg twice daily every 2 wk. Max: 2550 mg daily. With Insulin: Adults: Initial: 500 mg daily. Titrate: 500 mg every wk. Max: 2500 mg/day. Tab, ER, XR: With/Without Insulin: Adults: Initial: 500 mg daily with pm meal. Titrate: Increase by 500 mg every wk. Max: 2000 mg/daily. Children: Monotherapy and in combination with insulin in children above 10 yr and adolescent, 500 mg twice daily, adjust after 10-15 days. Max dose 2 gm daily taken as 2 or 3 divided doses.

Adverse Effects

GI upset, taste disturbance, rarely lactic acidosis, abnormal liver function tests, hepatitis, skin reactions, reduced B12 absorptions.

Risk Factor (Pregnancy/Lactation)

Pregnancy: No evidence of risk in humans. Lactation: Contraindicated or not recommended. Contraindications: Diabetic ketoacidosis or precoma, renal or hepatic impairment. Acute conditions predisposing to renal impairment. Cardiac or respiratory failure, recent MI, alcoholism. Administration of iodinated contrast materials. Discontinue for 48 hours before and after elective surgery. Precautions: Assess risk factors for lactic acidosis; discontinue immediately if metabolic acidosis suspected. Monitor renal function at least annually.

Interactions

Alcohol, iodinated contrast agents, diuretics, corticosteroids, ACE inhibitors, sympathomimetics, NSAIDs, other hypoglycaemics. Inhibitors of OCT2 (e.g., cimetidine, dolutegravir, ranolazine, trimethoprim).

Advice to Patient

Take with meals. Swallow extended release tablet whole without chewing or crushing. Report persistent abdominal discomfort, flatulence, diarrhoea, constipation or heart burn, unusual weakness or fatigue, unusual muscle pain, dizziness, drowsiness or light headedness, sudden respiratory difficulty, chest discomfort, slow or irregular heartbeat. Take prescribed diet, exercise regularly, control weight and check blood glucose level regularly. Avoid alcohol. Laboratory testing of glycosylated haemoglobin should be done every 3 months until blood glucose is controlled.

Pharmacokinetics

Onset of action: Within days, max effects up to 2 wks. Metabolism: Not metabolized by the liver. Bioavailability: Absolute: Fasting: 50%-60%. Half-life elimination: Plasma: 4-9 hrs. Blood: Approx. 17.6 hrs. Time to peak, serum: Immediate release: 2-3 hrs. Extended release: 7 hrs. (Range: 4-8 hrs). Excretion: Urine.

Brands with this active ingredient

• Admit 50/1000
• Admit 50/500
• Adrance M
• Aforal
• Alosita-Met
• Altin-Met
• Arjidap-M
• Biguanil
• Bryphage
• Bygliv-Met
• Celampa-M
• Comet
• Daglozin-M
• Dapa-Met
• Dapa-Met XR

Compiled by Healify Pharmacy from published drug references. How we compile it →

Always consult a pharmacist or doctor.