Diarrhea, nausea, vomiting, stomach upset, loss of appetite, changes in taste, and headache may occur. If any of these effects last or get worse, tell 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 right away if you have any serious side effects, including: new signs of infection (such as sore throat that doesn't go away, fever), easy bruising/bleeding, pale skin, unusual tiredness, fast/irregular heartbeat, mental/mood changes, signs of liver disease (such as nausea/vomiting that doesn't stop, dark urine, stomach/abdominal pain, yellowing eyes/skin), stiff neck, headache that doesn't go away, muscle weakness, extreme drowsiness, signs of low blood sugar (such as sudden sweating, shaking, fast heartbeat, hunger, blurred vision, dizziness, or tingling hands/feet).
This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: diarrhea that doesn't stop, abdominal or stomach pain/cramping, blood/mucus in your stool.
Do not use anti-diarrhea or opioid medications if you have any of these symptoms because these products may make them worse.
Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.
Get medical help right away if you have any very serious side effects, including: seizures.
A very serious allergic reaction to this drug is rare. However, get medical help right away 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 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.