Anopen-label trial, oropen trial, is a type ofclinical trial in which information is not withheld from trial participants.[1] In particular, both the researchers and participants know which treatment is being administered.[1] This contrasts with adouble-blinded trial, where information is withheld both from the researchers and the participants to reduce bias.[2][3]
Open-label trials may be appropriate for comparing two similar treatments to determine which is most effective, such as a comparison of differentprescriptionanticoagulants,[4] or possible relief fromsymptoms of some disorders when aplacebo is given.[5]
An open-label trial may still berandomized. Open-label trials may also be uncontrolled (without aplacebo group), with all participants receiving the same treatment.[4]
