Erythromycin is a broad-spectrum antibiotic that treats a host of bacterial infections, including those that cause bronchitis, pertussis, pneumonia, rheumatic fever, diphtheria, venereal disease, Legionnaire's disease and ear, eye and skin infections. MedlinePlus reports that erythromycin is also utilized as a preventative antibiotic prior to some types of surgery and dental procedures.
Discovered in 1949, erythromycin was first isolated from the metabolites produced by a strain of Streptomyces erythreus. Wikipedia notes that this bacterium was found in soil samples sent to an Eli Lilly research team by Abelardo B. Aguilar. In 1953, Eli Lilly filed a patent on the compound and began marketing it as an antibiotic under the name Ilosone.
Erythromycin is sold as a generic medication and also under the brand names Eryc, Ery-tab, Erythrocin and Pediamycin. It is most commonly prescribed as capsules and tablets that are also available in long-acting versions. Liquid and pediatric drops are prescribed to children as an alternative to pills. MedlinePlus states that erythromycin is generally taken every six to eight hours over the course of seven to 21 days, depending on the severity of the infection. Erythromycin is known to cause a number of side effects, particularly those that affect the gastrointestinal tract. Upset stomach, gastrointestinal tract discomfort, diarrhea, vomiting and stomach pain are common.