Does treatment present material risks?

The safety of anti-secretory treatment can only be confirmed by extensive use, although animal studies, human pharmacological investigations, and examination of outcome in controlled trials form essential preliminaries. The interpretation is, however, hindered by the confounding influence of disease present before treatment started, owing to coincident disease. Careful analysis of data is required to demonstrate this phenomenon, which is a major factor impeding the demonstration of drug-induced illness, which mimics ordinary disease. So far a substantial body of data which covers an extensive time after initial drug use has only been collected for cimetidine. This gives reassurance about drug safety during ordinary use, but confirms the difficulty caused by confounding. Studies of other drugs must take the same problems into account during interpretation.