warnings and cautions
5 WARNINGS AND PRECAUTIONS Renal impairment may occur. Assess renal function at the beginning of treatment and periodically during treatment. ( 5.1 ) Mesalamine-induced acute intolerance syndrome has been reported. Observe patients closely for worsening of these symptoms while on treatment. ( 5.2 ) Use caution when treating patients who are hypersensitive to sulfasalazine. ( 5.3 ) Mesalamine-induced cardiac hypersensitivity reactions (myocarditis and pericarditis) have been reported. ( 5.3 ) Hepatic failure has been reported in patients with pre-existing liver disease. Use caution when treating patients with liver disease. ( 5.4 ) Upper GI tract obstruction may delay onset of action. ( 5.5 ) Patients with pre-existing skin conditions have reported more severe photosensitivity reactions. ( 5.6 ) Use of mesalamine may lead to spuriously elevated test results when measuring urinary normetanephrine by liquid chromatography with electrochemical detection. ( 5.7 ) 5.1 Renal Impairment Renal impairment, including minimal change nephropathy, acute and chronic interstitial nephritis, and, rarely, renal failure, has been reported in patients given products such as mesalamine delayed-release tablets that contain mesalamine or are converted to mesalamine. It is recommended that patients have an evaluation of renal function prior to initiation of mesalamine therapy and periodically while on therapy. Exercise caution when using mesalamine in patients with known renal dysfunction or a history of renal disease. In animal studies, the kidney was the principal organ for toxicity [see Drug Interactions ( 7.1 ) and Nonclinical Toxicology ( 13.2 )]. 5.2 Mesalamine-Induced Acute Intolerance Syndrome Mesalamine has been associated with an acute intolerance syndrome that may be difficult to distinguish from an exacerbation of ulcerative colitis. Although the exact frequency of occurrence has not been determined, it has occurred in 3% of patients in controlled clinical trials of mesalamine or sulfasalazine. Symptoms include cramping, acute abdominal pain and bloody diarrhea, and sometimes fever, headache, and rash. Observe patients closely for worsening of these symptoms while on treatment. If acute intolerance syndrome is suspected, promptly discontinue treatment with mesalamine. 5.3 Hypersensitivity Reactions Some patients who have experienced a hypersensitivity reaction to sulfasalazine may have a similar reaction to mesalamine delayed-release tablets or to other compounds that contain or are converted to mesalamine. Mesalamine-induced cardiac hypersensitivity reactions (myocarditis and pericarditis) have been reported with mesalamine delayed-release tablets and other mesalamine medications. Take caution in prescribing this medicine to patients with conditions predisposing them to the development of myocarditis or pericarditis. 5.4 Hepatic Impairment There have been reports of hepatic failure in patients with pre-existing liver disease who have been administered mesalamine. Exercise caution when administering mesalamine to patients with liver disease. 5.5 Upper GI Tract Obstruction Pyloric stenosis or other organic or functional obstruction in the upper gastrointestinal tract may cause prolonged gastric retention of mesalamine which would delay mesalamine release in the colon. 5.6 Photosensitivity Patients with pre-existing skin conditions such as atopic dermatitis and atopic eczema have reported more severe photosensitivity reactions. 5.7 Interference with Laboratory Tests Use of mesalamine may lead to spuriously elevated test results when measuring urinary normetanephrine by liquid chromatography with electrochemical detection because of the similarity in the chromatograms of normetanephrine and mesalamine’s main metabolite, N-acetylaminosalicylic acid (N-Ac-5-ASA). Consider an alternative, selective assay for normetanephrine.