Arsphenamine is an organic arsenic compound that was marketed under the trade name Salvarsan. The drug was used to treat the infectious disease syphilis. It was usually administered intravenously or intramuscularly. The substance often caused severe side effects.
What is arsphenamine?
The drug was used to treat the infectious disease syphilis. Arsphenamine, also known as dioxydiamidoarsenobenzene, was discovered in 1907 by German physician and researcher Paul Ehrlich. It was the first effective chemotherapeutic agent to enter the pharmaceutical market. The drug replaced the highly toxic mercury compounds in the treatment of syphilis in the early 20th century. Today, thousands of people still suffer from this infectious disease, which is transmitted by the pathogen Treponema pallidum. Arsphenamine reacts with oxygen to form toxic compounds. For this reason, the substance had to be marketed in airtight ampoules. Despite its high efficacy, arsphenamine caused unpleasant and in some cases even very dangerous side effects.
Pharmacological action
For centuries, mankind suffered from the causative agent of syphilis. With the discovery of arsphenamine, it was possible to treat the disease for the first time. With this synthetic arsenic compound, its discoverer Ehrlich had, after numerous unsuccessful attempts, developed a drug that specifically attacked bacterial cells. On the other hand, the substance has no negative effects on human cells. The administration of arsphenamine significantly disrupts the energy metabolism of the pathogens. Often, just one injection is enough to weaken or even destroy the bacteria. A major disadvantage of the drug is its poor solubility and strong acidic reaction with distilled water. The acidic solution is not suitable for therapy, so it must be mixed with sodium hydroxide solution. The end product of this mixture is an alkaline liquid that can be used for therapeutic purposes. Due to the addition of sodium hydroxide, burns of muscle tissue and vein damage frequently occurred after intramuscular or intravenous injections of the preparation. Therefore, successor substances such as Neosalvarsan were developed, which are much better tolerated than Salvarsan. Despite their lower arsenic content, they are very effective. According to estimates by the World Health Organization, several million people are still infected with the sexually transmitted disease syphilis every year. Meanwhile, penicillin is successfully used to treat the disease because, unlike arsphenamine, it causes hardly any side effects.
Medical application and use
Although arsphenamine was primarily used to treat the venereal disease syphilis, it also serves as a medication for other infectious diseases. Usually, the sodium hydroxide-enriched compound was injected into veins or a skeletal muscle with the help of a syringe. The healing effect of the substance sometimes occurred after the first injection. As a rule, however, the injections were repeated three to four times with intervening breaks of several days or weeks in order to avoid disease relapses. Arsphenamine has a damaging effect on the cells of the pathogen and impedes its vital metabolic activities. Because of the toxic effect of this synthetic arsenic compound when it reacts with oxygen, it is transported in airtight containers. There, the basic substance can be kept for a long time, but must be used immediately after the injection solution is ready. Intravenous injection ensures a rapid effect, while intramuscular administration achieves a longer-lasting effect.
Risks and side effects
The drug arsphenamine had to give way to penicillin in the treatment of syphilis because it has too strong side effects. Shock reactions such as severe agitation or redness of the face and neck, chest tightness, drowsiness, or shortness of breath can occur just a few minutes after administration of the injection solution. Dangerous cerebral hemorrhages and pulmonary edema also cannot be ruled out. Dilution and slow injection of the substance can reduce side effects to a limited extent.Toxic reactions of the organism such as chills, fever, vomiting, pain in the limbs or acute failure of kidney functions may still occur several hours after the administration of arsphenamine. Gastrointestinal tract disorders are common. Side effects such as cardiovascular disease, blindness, deafness, paralysis and metabolic disorders are also known. Late effects, which can occur weeks later, include primarily blood, liver, and skin disorders, as well as damage to the central nervous system.
