Rx-to-OTC switches: trends and factors underlying success
Related Experiment Video
Updated: Aug 9, 2026

Transmembrane Domain Oligomerization Propensity determined by ToxR Assay
Published on: May 26, 2011
1Kline & Co., Little Falls, New Jersey 07424-0410, USA. Laura_Mahecha@klinegroup.com
Abstract:
The US Food and Drug Administration defines an Rx-to-OTC switch as over-the-counter (OTC) marketing of a drug product that was once a prescription (Rx) drug for the same indication, with the same strength, dose, duration of use, dosage form, population and route of administration. Here, we examine the rationale behind switches, the process of switches and historical case studies of switches in the United States to understand the factors for success and expected future trends.
Related Concept Videos
Factors Affecting Drug Response: Overview
Pharmaceutical Alternatives: Stability-Related Therapeutic Nonequivalence
Factors Affecting Drug Distribution: Miscellaneous Factors
Age plays a significant role due to differences in body composition among different age groups. Infants, for instance, have a higher proportion of total body water and lower albumin levels, a protein that binds drugs in the bloodstream. This unique composition in infants enhances the...
Impact of Pharmacokinetic–Pharmacodynamic Models: Regulatory Decisions
Modified-Release Drug Delivery Systems: Influencing Factors
Factors Affecting Drug Biotransformation: Biological
Species differences: Variations in enzyme systems across species can cause disparities in drug metabolism. For instance, humans may metabolize certain drugs faster than rodents, altering therapeutic effects.
Strain differences: Genetic variations within a species can result in differing enzyme activity, impacting drug response and toxicity. For example, some mouse strains may...

