Overview of radiopaque drugs: 1895–1931

Radiopaque (radiocontrast) agents are prescribed widely to improve radiographic images.1 They are mostly composed of numerous preparations of barium sulfate and organic iodides. Radiopaque drugs enhance pertinent aspects of the radiographic image and improve the image contrast (radiocontrast) and visibility of relevant anatomic loci. A historical account of the discovery and development of radiopaque drugs is worthwhile because it describes the past uses and toxicities of these drugs, which enhances understanding of current radiopaque pharmacotherapy. In late 1895, in Würzburg, Germany, Röntgen (often spelled Roentgen in English) submitted written documentation of his claim of discovering x-rays.2 Clinicians and scientists immediately realized that, except for the contrast between soft tissues and bone or gastrointestinal (GI) gas, useful images from x-rays were limited.3 By March 1896, the stomach of a dead guinea pig had been visualized by intragastric instillation of lead acetate as the radiopaque agent. Concurrently, oral administration of bismuth subnitrate successfully showed the esophagus and stomach of a patient and became the standard radiocontrast agent for the study of the alimentary tract.4,–6