Metformin is a first-line medication commonly prescribed to treat type 2 diabetes mellitus. Diabetes is a condition in which the body cannot properly process blood sugar, or glucose, into usable energy. High levels of blood sugar damage small capillaries, which can result in nerve and organ damage. Metformin reduces the liver's production of glucose, improves insulin sensitivity and decreases gastrointestinal absorption of glucose, states Drugs.com. High doses can cause serious side effects.
Lactic Acidosis
High doses of metformin may cause lactic acidosis, which is a rare but serious side effect, according to Drugs.com. Lactic acidosis is the elevation of lactic acid, which can cause a serious electrolyte imbalance. It is fatal in 50 percent of cases. The risk of lactic acidosis increases in patients with kidney disease and in older patients. Sign of lactic acidosis include malaise, myalgia, respiratory distress, somnolence and abdominal distress. Thus, a patient experiencing these side effects should not hesitate to seek emergency medical treatment. Once the doctor corrects the patient's electrolytes, he will likely prescribe a different medication to treat type 2 diabetes.
Hypoglycemia
A patient taking high doses of metformin may experience hypoglycemia, or low blood sugar levels. This occurs because high doses may be too effective in lowering blood sugar levels. In other cases, the patient may be eating less, which can result in hypoglycemia if the same high doses of metformin are given. Signs of hypoglycemia include anxiety, behavioral changes, blurry vision, cold sweats, confusion, pale skin, drowsiness, hunger, irregular heartbeat, nausea, shakiness and slurred speech. A patient experiencing any of these side effects should first drink juice or eat a piece of candy. If symptoms do not resolve, he should seek emergency medical treatment.
Diarrhea
In 53 percent of patients, diarrhea was a common side effect seen when taking high doses of metformin. This occurs because metformin alters chemical signals in the gastrointestinal tract to decrease sugar uptake. While beneficial in decreasing sugar uptake, it may also affect the gastrointestinal tract in other ways, which can cause diarrhea. Diarrhea may result in significant dehydration, nutrient deficiency and electrolyte imbalance if not properly managed. Thus, a patient experiencing diarrhea should not hesitate to seek medical treatment. The doctor will likely reduce the dose of metformin or prescribe a different medication to treat type 2 diabetes.
Member Comments