On the clinical evidence leading to tetrazepam withdrawal

In July 2013, the European Medicines Agency suspended the marketing authorizations of tetrazepam across the European Union. Herein, we examine the various kinds of adverse drug reactions (ADRs) reported to be associated with tetrazepam.

We undertook a two-sided systematic approach. First, we conducted a search in Medline for all studies that have published about tetrazepam ADRs in peer-reviewed journals. Second, we collected tetrazepam ADRs from pharmacovigilance system databases. Our study reveals discrepancies in the information provided by these two different sources, both in the number of cases reported as well as in the kind of reported ADRs. Whereas cutaneous alterations are the only ADRs reported in peer-reviewed journals, pharmacovigilance system databases include others (hepatobiliary, neurological and psychiatric).

We noted the lack of randomized controlled clinical trials evaluating tetrazepam efficiency and safety. We failed to find a turning point in the amount of ADRs reported following tetrazepam withdrawal to underpin the validity of the withdrawal. We stress the importance of a better communication of knowledge in scientific literature, pharmacovigilance agencies, and from doctors to prevent marketed usage of drugs with well-established side effects during long periods.