Date	Event	Description
20 July 2009	New citation required but conclusions have not changed	Some studies previously excluded on the basis of being crossover design and unable to extract first arm have been moved to included studies and added to the 'Risk of bias' tables. Some lesser adverse events have been reported in this review which were not pre‐specified in the methods section. Review will no longer be updated.
6 July 2009	New search has been performed	New search run. One study identified which superseded a previously included abstract. Review reformatted and closed to further updating due to lack of new evidence likely to alter findings. Some studies previously excluded as crossover design added to included trials.