How do medicines work?
Drugs Bind to Their Receptors Many drugs exert their physiological effects by binding to specific sites, called receptors , on the surface of certain cells . A drug binds to a receptor using the same kinds of bonding interactions—van der Waals interactions, dipole–dipole interactions, hydrogen bonding—that molecules use to bind to each other. The most important factor in the interaction between a drug and its receptor is a snug fit. Therefore, drugs with similar shapes and properties, which causes them to bind to the same receptor, have similar physiological effects. For example, each of the compounds shown here has a nonpolar, planar, six-membered ring and substituents with similar polarities. They all have anti-inflammatory activity and are known as NSAIDs (non-steroidal anti-inflammatory agents). Salicylic acid has been used for the relief of fever and arthritic pain since 500 b.c. In 1897, acetylsalicylic acid (known by brand names such as Bayer Aspirin, Bufferin,...
