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Drug Action and Pharmacodynamics: Overview |  |
| Pharmacodynamics is the study of the biochemical and physiologic effects of drugs and their mechanisms of action. It considers both drug action, which refers to the initial consequence of a drug-receptor interaction, and drug effect, which refers to the subsequent effects. The drug action of digoxin, for example, is inhibition of membrane Na+/K+ -ATPase; the drug effect is augmentation of cardiac contractility. |
| Not all drugs exert their pharmacologic actions via receptor-mediated mechanisms. The action of some drugs—including inhalation anesthetic agents, osmotic diuretics, purgatives, antiseptics, antacids, chelating agents, and urinary acidifying and alkalinizing agents—is attributed to their physicochemical properties. Certain cancer and antiviral chemotherapeutic agents, which are analogs of pyrimidine and purine bases, elicit their effects when they are incorporated into
nucleic acids and serve as suicide substrates for DNA or RNA synthesis. The effect of most drugs, however, results from their interactions with receptors. These interactions and the resulting conformational changes in the receptor initiate biochemical and physiologic changes that characterize the drug’s response. |
