A medication commonly prescribed for nausea in pregnancy was approved in part based on a 40-year-old study with a major flaw, as revealed by a recent reanalysis of the old study. The drug pyridoxine-doxylamine is sold in Canada under the brand name Diclectin (Diclegis in the United States), is the rebranded version of an earlier medication called Bendectin. The old study is known as “the eight-way Bendectin Study”, in which women were randomly assigned to eight groups. Of those, one received a placebo and the other seven a variety of drugs including pyridoxine-doxylamine.
A pair of researchers from the University of Toronto (Rujun Zhang and Navindra Persaud) got hold of 36,000 pages of information on Bendectin from the US FDA and Health Canada. Their reanalysis, which appears in PLOS ONE, casts doubts over the morning-sickness drug due to several methodological defects. These include the loss of massive amounts of data, widespread inconsistencies in how physicians recorded symptoms of morning sickness, a high rate of dropouts from the study, and, most damning of all, the unavailability of the raw data of the study.
Bottom line, according to the Toronto researchers: “the prescribing of this medication should not be based on this trial.”
This data trove is only the latest unearthed by the “Restoring Invisible and Abandoned Trials” (RIAT) initiative. Launched in 2013 by the BMJ, PLOS, and a group of scientists, the goal of RIAT is to give researchers, regulators, clinicians, and patients access to data that have long been hidden from sight and which might have been prone to bias.