Discover the workings of anti-infective drugs.

For thousands of years, medicines were administered based on age-old traditions which were discovered through trial and error methods. The modern era of the Pharmaceutical Industry began in the 19th century. In the 20th century, the unification of research in the fields such as chemistry and physiology aided the drug discovery process.

The history of drug discovery
In the beginning of the 19th century, a number of important compounds were isolated from plants. An important discovery was that of morphine (1804), which was isolated from opium. The discovery of cocaine (1860) from coca leaves was an important discovery as a local anaesthetic.
At that time, the focus of developing medicines was for pain relief. Initially, surgeons used ether as an anaesthetic during surgery, following which chloroform was used. The discovery of these two agents revolutionised the practise of surgery, thus enabling longer and more complex surgical procedures to be carried out.

The discovery of anti-infective drugs
Prior to the discovery of anaesthesia, many patients lost their lives during surgery on account of the pain associated with it. Also, there were a number of cases wherein the wounds would become infected resulting in the death of the patients. In fact, infectious diseases were one of the leading causes of death in most parts of the world. The discovery of phenol as an anti infective agent by Joseph Lister led to the beginning of the antiseptic surgery in England.

The most important discovery in the prevention of infectious diseases was the introduction of the smallpox vaccine. As a result, the use of vaccines and the implementation of public health measures decreased the impact of infectious diseases. The first pharmaceutical treatment for infectious disease was the discovery of arsphenamine which was developed by Paul Ehrlich for treating syphilis. Arsphenamine was marketed with the trade name of Salvarsan and was used to treat syphilis until the 1940s, after which it was replaced by penicillin.

Thus, the discovery of anti-infective treatment began with the industrial production of pencillin in 1941. This was followed by the discovery and development of streptomycin in 1944, chloramphenicol in 1947, chlortetracycline in 1948, the macrolides in 1952, semisynthetic penicillins, cephalosporins and glycopeptides from 1958 onwards, streptogramins and quinolones in 1962, fluoroquinolones in the 1980s, and finally, oxazolidinones and cationic peptides in the 1990s.

What do anti-infective agents treat?
Anti-infective agents are used to treat disorders caused by bacteria, viruses, protozoa, worms, fungi, and yeast.

Thus, we can safely say that the discovery of anti-infective agents was one of the most important medical achievements of the twentieth century.