| The most frequent adverse reactions seen in clinical trials are diarrhoea (3%), nausea (3%), abdominal pain (3%), headache (3%), vomiting (1%) and rash (1%). Hypersensitivity reactions and drug fever may occasionally occur Frequency of adverse effects, based on clinical trials and reports from post-marketing surveillance System Organ Classes | Common 1/100 to <1/10
| Rare 1/10,000 to 1/1,000
| Very rare 1/10,000
| Not Known | Blood and the lymphatic system disorders | | | Eosinophilia (as part of an allergic reaction) Anaemia Aplastic anaemia Leukopenia (incl. Granulocytopenia) Thrombocytopenia Agranulocytosis Pancytopenia | | Immune system disorders | | | | Hypersensitivity reaction | Nervous system disorders | Headache | | Peripheral neuropathy Benign intracranial hypertension in adolescents | | Cardiac disorders | | Myocarditis* Pericarditis* | | | Respiratory, thoracic and mediastinal disorders | | | Allergic lung reactions (incl. dyspnoea, cough, allergic alveolitis, pulmonary eosinophilia, lung infiltration, pneumonitis) | | Gastrointestinal disorders | Diarrhoea Abdominal pain Nausea Vomiting | Pancreatitis* Increased amylase (blood and/or urine) | | | Hepato-biliary disorders | | | Increased liver enzymes and bilirubin, hepatotoxicity (incl. hepatitis*, cirrhosis, hepatic failure) | | Skin and subcutaneous tissue disorders | Rash, (incl. urticaria, erythematous rash | | Reversible alopecia Quincke's oedema | | Musculoskeletal, connective tissue and bone disorders | | | Myalgia Arthralgia Single cases of lupus erythematosus-like reactions | | Renal and urinary disorders | | | Renal impairment, interstitial nephritis*, nephrotic syndrome, urine discolouration | | General disorders and administration site conditions | | | | Drug fever | (*) The mechanism of mesalazine-induced myo- and pericarditis, pancreatitis, nephritis and hepatitis is unknown, but it might be of allergic origin.It is important to note that several of these disorders can also be attributed to the inflammatory bowel disease itself. | |