Every medication has side effects; however, it is rare that they may occur. Patients can usually find the complete list of side effects with their medication. Serious side effects may include: Allergic reaction including hives, difficulty breathing, swelling of your face, lips, Tongue, or throat, Severe stomach pain or cramping, Fever, Headache, Bloody diarrhea Common serious side effects may include: Mild nausea or vomiting, Stomach cramps, Diarrhea, Gas, Fever, sore throat, or other flu symptoms, Constipation, Headache or dizziness, Fatigue, Skin rash Important: Call your doctor if you find undissolved tablets in your stool. This is not a complete list of side effects and others may occur. Call your doctor for medical advice about additional side effects or any side effect that bothers you or that do not go away.