Allergy to sulphasalazine. Closely monitor patients w/ chronic lung function, especially asthma due to risk of hypersensitivity reactions. Patients w/ conditions predisposing to the development of myo- or pericarditis; do not reintroduce treatment if hypersensitivity reaction is suspected. Perform haematological investigations if patient develops unexplained bleeding, bruising, purpura, anaemia, fever or sore throat. Terminate treatment if blood dyscrasia is suspected. W/draw promptly in suspected acute intolerance syndrome. May delay onset of action in organic or functional obstruction in upper GIT. May lead to false elevated results when measuring urinary normetanephrine by liqd chromatography w/ electrochemical detection. Ensure adequate fluid intake during treatment. Hepatic impairment. Patients w/ confirmed mild to moderate renal impairment. Evaluate renal function prior to initiation of therapy & at least twice a yr while on treatment. Pregnancy & lactation. Not recommended in childn <18 yr.