Dizziness, dry mouth, difficulty sleeping, irritability, nausea, vomiting, diarrhea, or constipation may occur. If 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: fast/irregular/pounding heartbeat, mental/mood changes (e.g., agitation, uncontrolled anger, hallucinations, nervousness), uncontrolled muscle movements, change in sexual ability/interest.Stop taking this medication and seek immediate medical attention if any of these rare but very serious side effects occur: severe headache, slurred speech, seizure, weakness on one side of the body, vision changes (e.g., blurred vision).This drug may infrequently cause serious (sometimes fatal) lung or heart problems (pulmonary hypertension, heart valve problems). The risk increases with longer use of this medication and use of this drug along with other appetite-suppressant drugs/herbal products. If you notice any of the following unlikely but very serious side effects, stop taking this medication and consult your doctor or pharmacist immediately: chest pain, difficulty breathing with exercise, decreased ability to exercise, fainting, swelling of the legs/ankles/feet.A very serious allergic reaction to this drug is rare. However, seek immediate medical attention 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.