ABSTRACT
This chapter focuses on drug-drug interactions and their effect on the market place. Terfenadine was introduced into the marketplace as the first nonsedating histamine-1 receptor antagonist. Seldane held market exclusivity as a nonsedating antihistamine from its launch in 1985 until 1989, when astemizole entered the market. In 1991, 17 million prescriptions were issued, and there were more than 100 million users of Seldane worldwide. Cimetidine was launched in the United States as a first-in-class compound in 1977. It held virtually 100% of the US prescription antiulcerant market from 1977 to 1981. Tagamet was eventually approved for twice-daily dosing, but not in time to prevent the market uptake of Zantac. However, the adverse drug-drug interactions attributed to Tagamet also played a prominent role in the marketing strategy and success of Zantac and other competitors. The increasingly competitive marketplace requires that every possible advantage be highlighted, particularly with the more extensive use of direct-to-consumer advertising.
