Dizziness, drowsiness, weakness, blurred vision, dry eyes, dry mouth, nausea, constipation, and abdominal bloating may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. To relieve dry mouth, suck (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute. To relieve dry eyes, consult your pharmacist for artificial tears or other eye lubricants. To prevent constipation, eat a diet adequate in fiber, drink plenty of water, and exercise. Consult your pharmacist for help in selecting a laxative (such as a stimulant type with stool softener). 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: decreased sweating, dry/hot/flushed skin, fast/irregular heartbeat, loss of coordination, slurred speech, fainting, uncontrollable/unusual muscle movements, mental/mood changes (such as confusion, agitation, unusual excitement, depression, strange thoughts), eye pain, vision changes, difficulty urinating, decreased sexual ability, slow/shallow breathing. Tell your doctor immediately if any of these rare but serious side effects occur: signs of infection (such as fever, persistent sore throat), signs of liver problems (dark urine, persistent nausea, vomiting, stomach/abdominal pain, yellowing eyes/skin, unusual tiredness). A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: 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.