All of the following are contraindications for the use of metformin except -

Ans. is 'd' i.e., Hypokalemia Metformin* Metformin is a biguanide, improves insulin resistance in patients with Type II DM.Mechanism of action* Upregulation of AMP dependant protein kinases acts only in presence of insulin and therefore not used in Type I DM patients.Side effects* Abdominal pain, anorexia, nausea, metallic taste, mild diarrhoea and tiredness are the frequent side effects.* Lactic acidosis: Small increase in blood lactate level occurs with metformin, but lactic acidosis is rare (<1% per 10,000 patient years) because it is poorly concentrated in hepatic cells. Alcohol ingestion can precipitate severe lactic acidosis.* Vitamin B 12 deficiency due to interference with its absorption can occur with high dose of metformin.* In addition to general restrictions for use of oral hypolycaemic, metformin is contraindicated in hypotensives, heart failure, severe respiratory, renal and hepatic failure, heart failure and alcoholics as it may aggravate lactic acidosis.