The easiest way to create a new drug is to modify an existing one. These so-called drug analogs account for about half of all "new" drugs and are of tremendous importance both for medical and financial reasons. In addition, drug analogs can be modeled on naturally occurring bioactive substances that do not make good drugs on their own, thereby considerably increasing the therapeutic range of pharmaceutical medicine.This first authoritative and systematic overview of past and current strategies for successful drug development by modification spans all important drug classes and all major therapeutic fields. It discusses analog-based drug discovery for, among others, beta-blockers, ACE inhibitors, steroids, opiates, coxibs, stigmines, proton pump inhibitors, platinum compounds and quinolones. In addition, case studies on selected commercially successful drug analogs provide prime advice for new drug development projects based on modification.The book is rounded off with an exclusive table of the 1,000 most successful drug analogs according to IMS ranking, classified in terms of chemical structure, mode of action and patentability.Officially endorsed by the International Union of Pure and Applied Chemistry's Drug Development Committee, indispensable for medicinal and pharmaceutical chemists in all fields.