Nausea, vomiting, diarrhea, loss of appetite, or headache 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: muscle weakness, mental/mood changes, new lump/growth in the neck (goiter), signs of low blood sugar (e.g., shaking, dizziness, blurred vision, unusual hunger).
Tell your doctor immediately if any of these highly unlikely but very serious side effects occur: blood in the urine, change in the amount of urine.
Seek immediate medical attention if any of these highly unlikely but very serious side effects occur: confusion, persistent headache, neck stiffness, seizures.
This medication may rarely cause serious (possibly fatal) allergic reactions and other side effects such as a severe peeling skin rash (e.g., Stevens-Johnson syndrome), blood disorders (e.g., agranulocytosis, aplastic anemia), liver damage, or lung injury. If you notice any of the following, seek immediate medical attention: skin rash/blisters, itching, swelling, persistent sore throat or fever, paleness, joint pain/aches, persistent cough, trouble breathing, easy bleeding/bruising, yellowing eyes or skin, persistent nausea/vomiting, unusual fatigue, dark urine.
This medication may rarely cause a severe intestinal condition (pseudomembranous colitis) due to a resistant bacteria. This condition may occur while receiving therapy or even weeks after treatment has stopped. Do not use anti-diarrhea products or narcotic pain medications if you have the following symptoms because these products may make them worse. Tell your doctor immediately if you develop: persistent diarrhea, abdominal or stomach pain/cramping, or blood/mucus in your stool.
Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection (oral or vaginal fungal infection). Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge or other new symptoms.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.