An allergic reaction to this drug can be serious and will be characterized by the presence of hives, breathing problems, or swelling of the face, tongue, or throat. Other side effects which will need to be reported at once to the appropriate medical personnel include the following reactions: rashes on the skin, paled skin, bloody or watery diarrhea, abnormal bruising or bleeding, increased restlessness, confusion, seizures, hallucinations, weakened pulse or heart rate, loss of appetite, nausea, abdominal pain, jaundice, chills and fevers, a decrease or discoloration in urine, clay-colored bowel movements, or general flu symptoms. Some side effects that are not as serious, but should still be monitored, are a swollen tongue, joint pain, dizziness, insomnia, or a ringing sound in the child's ears.