Open-label trial

From Wikipedia the free encyclopedia

An open-label trial, or open trial, is a type of clinical 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 a double-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 different prescription anticoagulants,[4] or possible relief from symptoms of some disorders when a placebo is given.[5]

An open-label trial may still be randomized. Open-label trials may also be uncontrolled (without a placebo group), with all participants receiving the same treatment.[4]


  1. ^ a b "Open label study". National Cancer Institute, US National Institutes of Health. 2020. Retrieved 20 November 2020.
  2. ^ "Double-blind (trial)". Merriam-Webster Medical Dictionary. 2020. Retrieved 20 November 2020.
  3. ^ "Double-blind study"., Office of AIDS Research, US National Institutes of Health. 2020. Retrieved 20 November 2020.
  4. ^ a b Beyer-Westendorf, J.; Buller, H. (2011). "External and internal validity of open label or double-blind trials in oral anticoagulation: better, worse or just different?". Journal of Thrombosis and Haemostasis. 9 (11): 2153–2158. doi:10.1111/j.1538-7836.2011.04507.x. ISSN 1538-7933. PMID 21920015.
  5. ^ Ballou, Sarah; Kaptchuk, Ted J.; Hirsch, William; Nee, Judy; Iturrino, Johanna; Hall, Kathryn T.; Kelley, John M.; Cheng, Vivian; Kirsch, Irving; Jacobson, Eric; Conboy, Lisa; Lembo, Anthony; Davis, Roger B. (25 May 2017). "Open-label versus double-blind placebo treatment in irritable bowel syndrome: study protocol for a randomized controlled trial". Trials. 18 (1): 234. doi:10.1186/s13063-017-1964-x. ISSN 1745-6215. PMC 5445390. PMID 28545508.