Review Question - QID 102587

Metformin is contraindicated in renal failure, sepsis, severe heart failure, liver dysfunction, and patients at risk for renal failure, such as prior to a contrast load for angiography. Mild chronic obstructive pulmonary disease is not a contraindication for metformin.

The biguanide metformin is considered the first-line pharmacologic treatment of type II diabetes mellitus (DMII). Although its exact mechanism is unclear, its major effect is to decrease hepatic glucose release. The most commonly-cited side-effect of metformin use, though uncommon, is lactic acidosis. Signs and symptoms of lactic acidosis are somewhat non-specific and include nausea, vomiting, and Kussmaul breathing.

Ripsin et al. discuss the management strategy of DMII and comment that metformin is the only pharmacologic agent shown to decrease mortality rates in these patients. They also state that Cr > 1.5 in men or > 1.4 in women are evidence of renal insufficiency and are contraindications to metformin use.

Eurich et al. performed a systematic review of the literature for metformin use in DMII and heart failure. The cohort studies analyzed did not demonstrate any evidence of worsening morbidity and mortality in patients taking metformin, even in those patients who demonstrated reduced left ventricular ejection fraction or concomitant renal failure.

Incorrect answers:
Answer 1: Hepatitis resulting in liver dysfunction is a contraindication for metformin use.
Answer 3: Congestive heart failure is a contraindication for metformin use.
Answer 4: Alcohol abuse can lead to liver damage, which is a contraindication to metformin use.
Answer 5: Patients preparing to undergo procedures in which they will receive contrast should discontinue metformin until Cr is normal after the procedure.