Headache, nausea, tiredness, or cough may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as depression, anxiety, confusion), signs of kidney problems (such as a change in the amount of urine), unusual thirst.

Rarely, this medication can cause severe (sometimes fatal) liver and blood problems (lactic acidosis). Tell your doctor right away if you develop symptoms of liver problems (such as nausea/vomiting that doesn’t stop, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine) or lactic acidosis (such as deep/rapid breathing, drowsiness, nausea/vomiting, unusual weakness).