Dear Richard and Graham, and any other interested folks,
Richard, BRAVO, BRAVO, AND MORE BRAVO! Good detective work there!
Graham, get the "paper insert" for the Pentasa (Mesalazine, I believe), and for the Mesalamine, both being aspirin derivative, anti-inflammatory meds, I think. Get the "insert" from the pharmacist who SOLD you the drug (or from any helpful, caring pharmacist whom you know.