- Potassium bromide (KBr) is a white, crystalline, highly water-soluble ionic salt composed of potassium (K⁺) and bromide (Br⁻) ions. It resembles common table salt in appearance and taste but has markedly different chemical and pharmacological properties.
- Potassium bromide has a long and diverse history of use in medicine, photography, chemical analysis, and various industrial processes.
- In medicine, potassium bromide was historically one of the earliest anticonvulsant drugs introduced in the 19th century. It was widely used to treat epilepsy and seizure disorders, as well as to calm nervous agitation and hysteria, due to its sedative and central nervous system depressant effects. The bromide ion acts by stabilizing neuronal membranes and inhibiting excessive electrical activity in the brain. While its use in human medicine has largely been discontinued in favor of safer and more effective anticonvulsants, potassium bromide is still used veterinarily, especially in canine epilepsy management, often as an alternative to or in combination with phenobarbital.
- In the chemical industry, potassium bromide is used in analytical chemistry, particularly in infrared (IR) spectroscopy. It is commonly pressed into clear, transparent pellets that serve as an optically transparent medium for examining solid samples in the IR region. KBr’s lack of significant IR absorption in most relevant wavelengths makes it ideal for this application. It is also used as a reagent in various chemical syntheses, particularly in organic and pharmaceutical chemistry.
- Potassium bromide has applications in the photographic industry, where it serves as a restrainer in black-and-white photography. It helps reduce fogging and improves the clarity of the final image by moderating the development process of silver halide films.
- In veterinary and animal sciences, beyond its role in epilepsy treatment, potassium bromide may also be used experimentally in animal models for neurological research. Its effects on the nervous system have made it a subject of interest in studies exploring ion channel modulation and neuroinhibition.
- Although generally well-tolerated at therapeutic levels, potassium bromide can cause a range of side effects when used in high doses or over extended periods. These may include lethargy, behavioral changes, gastrointestinal upset, skin eruptions (bromoderma), and neurological impairments, collectively known as bromism—a condition resulting from bromide toxicity. Because bromide is eliminated slowly from the body, especially in individuals with renal impairment, it can accumulate and lead to toxicity if not properly monitored.
- Environmentally, potassium bromide is stable and non-flammable, and the bromide ion occurs naturally in seawater and some mineral deposits. However, excessive bromide can interfere with water disinfection processes, leading to the formation of potentially harmful disinfection by-products like bromate, especially in chlorinated or ozonated water systems.
