Is informed consent necessary for randomized Phase IV 'observational' drug studies?

This article addresses the question about whether informed consent (IC) can be waived in Phase IV randomized observational drug studies (P4RODSs). To do this, it was first necessary to establish that the term P4RODS is a contradiction precisely because randomization necessarily makes a study 'interventional', hence P4RIDS. Once this was established we argued that, based on the right and the harm principles, universally waiving IC in P4RIDS is ethically unjustifiable. Looking into public health and the nature of equipotent and bioequivalent drugs were also insufficient rationale to justify circumstantial waiving of IC. We conclude that IC can never be waived in P4RIDS, although an opt-out procedure in minimal risk studies could be ethically acceptable.