Headache, sore throat, trouble sleeping, malaise, and nausea 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.This drug may rarely cause serious (possibly fatal) liver disease. Seek immediate medical attention if you notice any of the following unlikely but very serious side effects: severe stomach/abdominal pain, persistent nausea/vomiting, unusual tiredness, yellowing of the eyes/skin, dark urine.If your doctor determines that you have experienced liver problems from this medication, do not take it again.Tell your doctor immediately if any of these rare but very serious side effects occur: mental/mood changes (e.g., agitation, aggression, hallucinations, abnormal dreams, depression, suicidal thoughts/suicide), worsening shortness of breath, tingling of the hands/feet, muscle/joint aches, coughing up blood, swelling of the hands/feet, chest pain, easy bruising/bleeding, signs of infection (e.g., fever, persistent sore throat).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.