Pathogenesis of fibrosing colonopathy: the role of methacrylic acid copolymer.

Fibrosing colonopathy is a serious bowel disorder which was first seen in 1991 in patients with cystic fibrosis treated with high doses of pancreatic enzyme supplements. Epidemiological evidence from two case-control studies, temporal data and direct experimental evidence support the conclusion that there is a causal relationship between the disease and intake of high doses of the excipient, methacrylic acid copolymer, which is used to coat certain brands of pancreatic enzyme. A high intake of lipase, the active ingredient in pancreatic enzymes, is not a risk factor for fibrosing colonopathy in the absence of methacrylic acid copolymer. Excipients may be toxic if used in new patient populations such as children and in doses exceeding the safe levels predicted by animal toxicology.