Relatively low systemic exposure of substance with probably non-CYP metabolism. Acetyl salicylic acid is an inducer of CYP 2C19 Two references state non-porphyrinogenicity.

Antiinflammatory agent perorally used 1 g/d, in ulcerating colitis. Composed of two mesalazine ( 5-amino-salicylic acid) molecules joined by azo-bonding. Only insignificantly (1-2 %) absorbed, split by colon bacteria into two 5-ASA, which is acetylated in the gut and the liver. mesalazine: South African list: use. EPI-list: use