Mesalazine is the active moiety of sulfasalazine, which is metabolized to sulfapyridine and mesalazine. Sulfapyridine (INN; also known as sulphapyridine) is a sulfanilamide antibacterial medication. The medication is broken down by intestinal bacteria into sulfapyridine and 5-aminosalicylic acid. He remembered Lock having Sulfapyridine treatment and being "vociferous". Sulfapyridine is no longer prescribed for treatment of infections in humans.