A comprehensive review addressing the factors influencing generic drug substitution

Generic drug substitution is a common practice in healthcare systems worldwide to promote cost-saving treatments while maintaining therapeutic effectiveness. Several factors influence this substitution, including regulatory policies, safety and efficacy considerations, patient and physician preferences, and market dynamics. This review comprehensively analyzes how these factors interact and influence generic drug substitution in healthcare settings and across various therapeutic classes and highlight the importance of balancing cost-saving measures with maintaining patient safety and therapeutic efficacy. Policies and guidelines established by health authorities in each country influence the approval, interchangeability, and substitution of generic drugs. Bioequivalence and therapeutic equivalence are critical factors, particularly in drugs with narrow therapeutic indexes. Moreover, physicians’ acceptance and willingness to prescribe generic drugs, as well as patient acceptance and compliance with generic drug use, play a vital role in promoting generic substitution.