The safety profile of the paediatric formulation is similar to that of the 250-mg tab in adult patients. The majority of adverse events reported were of the gastrointestinal system, eg diarrhea, vomiting, abdominal pain, dyspepsia and nausea. Other adverse events included headache, altered taste and transient elevations of liver enzymes. Allergic reactions ranging from urticaria and mild skin eruptions to anaphylaxis have occurred with orally administered clarithromycin. There have been reports with oral clarithromycin of transient CNS side effects including anxiety, dizziness, insomnia, hallucinations, bad dreams and confusion; however, a cause and effect relationship has not been established.