Generics: need for clinical concern?

The market of generic drugs is in continuous development in all countries, including Belgium. Their low cost explains their success in western and developed countries. However, clinical concerns have been raised when generics are used. Indeed, various studies suggest that generic substitution can be associated with reduced efficacy or (and) increased side-effects, particularly with drugs used in severe diseases or pathological states such as epilepsy, cardiac arrhythmia, prevention of graft-rejection, ... The generic drugs must have systemic bioavailability similar to that of the original drug. Thus, they have supposed similar therapeutic bioequivalence. However, similar pharmacokinetics does not imply identical therapeutic activity, particularly with drugs having narrow therapeutic indices such as anti-epileptics, anti-arrythmics ... In this case, switchability rather than prescribability may cause problems. Low pharmaceutical quality is more frequent when drugs are produced in certain countries, in some cases causing a real concern when activity and safety are considered.