Abstract
The escalating healthcare expenditure is a major challenge to sustainability of the healthcare systems. To confront the escalating health expenditure in general and medicines expenditure in particular, many countries promoted the use of generic medicines. To promote generic medicines, many countries have adopted a generic substitution (GS) policy and generic prescribing. To effectively implement the GS policy, it is evident in the literature that it is essential to have an evidence-based guide on therapeutic equivalence and formulary of interchangeable medicines to guide responsible GS. In Saudi Arabia, GS is permissive and pharmacists are given the right to perform GS. While the prescriber's approval is not a requirement, patient consent is required when performing GS. Although there are some general drug references, such as the Saudi National Formulary (SNF) and list of registered medicines in the Saudi market, but there is currently no information available to healthcare professionals that documents the therapeutic and bioequivalence between medicines. Thus, it is essential to have a formulary of interchangeable medicines to guide appropriate GS or at least to include such vital information regarding therapeutic equivalence and brand interchangeability as part of the SNF. That, in turn, will not only make healthcare professionals more confident when providing GS, but will also enable the avoidance of situations where GS is inappropriate.