See also Warning section. Drowsiness, dizziness, dry mouth, blurred vision, constipation, weight gain, or trouble urinating may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute. To prevent constipation, maintain a diet adequate in fiber, drink plenty of water, and exercise. If you become constipated while using this drug, consult your pharmacist for help in selecting a laxative. 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 rare but serious side effects occur: easy bruising/bleeding, persistent heartburn, shaking, mask-like facial expressions, muscle spasms, severe stomach/abdominal pain, decreased sexual ability/desire, enlarged/painful breasts. Seek immediate medical attention if any of these rare but very serious side effects occur: black stools, vomit that looks like coffee grounds, severe dizziness, fast/irregular heartbeat, fainting, seizures. This medication may rarely cause a very serious condition called serotonin syndrome. The risk increases when this medication is used with certain other drugs (see Drug Interactions section). Seek immediate medical attention if you develop some of the following symptoms: hallucinations, unusual restlessness, loss of coordination, unexplained fever, severe nausea/vomiting/diarrhea, twitching muscles. This medication may rarely cause a serious condition called neuroleptic malignant syndrome (NMS). Seek immediate medical attention if you develop the following: unexplained fever, muscle stiffness, severe confusion, sweating. 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.