Headache, stomach pain, loss of appetite, trouble sleeping, dizziness, nausea, vomiting, lightheadedness, irritability, nervousness, blurred vision, dry mouth, constipation or (rarely) drowsiness may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. 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 immediately if any of these unlikely but serious side effects occur: uncontrolled movements (motor tics or tremor), verbal tics (e.g., Tourette's syndrome), weight loss, fast/pounding/irregular heartbeat, mental/mood/behavior changes (e.g., agitation, aggression, mood swings, depression, abnormal thoughts), difficulty urinating. Tell your doctor immediately if any of these rare but very serious side effects occur: signs of infection (e.g., fever, persistent sore throat), easy bruising/bleeding. Seek immediate medical attention if any of these rare but very serious side effects occur: shortness of breath, chest pain, jaw/left arm pain, fainting, seizures, sudden vision changes, weakness on one side of the body, slurred speech, confusion. A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: 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.