Technique used	Old drug	New drug	Comment
Combination product	Alendronate (Fosamax)	Alendronate plus vitamin D (Fosavance*)	Supplemental calcium still needed with Fosavance,* and Fosavance* is more expensive than generic alendronate plus calcium and vitamin D
Isomers	Cetirizine (Zyrtec)	Levocetirizine (Xyzal)	No evidence suggesting superiority of levocetirizine over cetirizine
	Citalopram (Celexa)	Escitalopram (Lexapro)	No compelling evidence suggesting superiority of escitalopram over citalopram
	Loratadine (Claritin)	Desloratadine (Clarinex)	No reason to use desloratadine instead of loratadine, and desloratadine is more expensive
	Omeprazole (Prilosec)	Esomeprazole (Nexium)	No evidence of therapeutic advantage of esomeprazole over omeprazole when used at equivalent therapeutic doses
Metabolites	Terfenadine*	Fexofenadine (Allegra)	Fexofenadine is a metabolite of terfenadine,* which retains antihistaminic activity with fewer unwanted cardiac effects
Modified-release formulation	Doxazosin tablet (Cardura)	Doxazosin extended-release tablet (Cardura XL)	Immediate-release formulation as effective as extended-release, with no significant difference in adverse effects