Stomach upset and itching may occur. If either of these effects lasts or gets worse, tell your doctor or pharmacist promptly. Remember that this medication has been prescribed because your doctor 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: numbness/tingling (especially of the arms/legs, around the mouth/tongue), strange feeling on the skin of the arms/legs, mental/mood changes (such as confusion, psychosis, seizures), difficulty walking, unsteadiness, slow/shallow/troubled breathing, dizziness/feeling of spinning, unexplained fever, trouble speaking, muscle weakness, signs of kidney problems (such as change in the amount of urine), red/pink urine. This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. 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. If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse. Use of this medication for prolonged or repeated periods may result in a new infection. Tell your doctor if you notice any symptoms of a new infection (such as white patches in your mouth, a change in vaginal discharge). 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.

Some products that may interact with this drug include: cephalothin.