See also Warning and Precautions sections.Dizziness, lightheadedness, tiredness, and nausea may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.This drug may reduce blood flow to your hands and feet, causing them to feel cold. Smoking may worsen this effect. Dress warmly and avoid tobacco use.Remember that your doctor has prescribed this medication because he or she 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 any of these unlikely but serious side effects occur: very slow heartbeat, severe dizziness, fainting, trouble breathing, blue fingers/toes, mental/mood changes (such as confusion, mood swings, depression).Although this medication may be used to treat heart failure, some people may rarely develop new or worsening symptoms of heart failure. Tell your doctor right away if you experience any of these unlikely but serious side effects: swelling ankles/feet, severe tiredness, shortness of breath, unexplained/sudden weight gain.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any of the following symptoms of a serious allergic reaction: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.