Inclusion criteria for pharmacodynamic and clinical trials in chronic idiopathic constipation: pitfalls in using Rome III for functional constipation

Selection of the appropriate patients to take part in any pharmacodynamic or clinical trial is essential for the context and relevance of the trial and to realistically assess the efficacy and safety of an experimental treatment for the condition of interest. There is continued interest in the development of medications for chronic idiopathic constipation or constipation resulting from use of opiates.