Spectinomycin, sold under the tradename Trobicin among others, is an antibiotic useful for the treatment of gonorrhea infections. It is given by injection into a muscle. Common side effects include pain at the area of injection, rash, nausea, fever, and trouble sleeping. Severe allergic reactions may occasionally occur. It is generally safe to use during pregnancy. It may be used by those who are allergic to penicillin or cephalosporins. It is in the aminocyclitol class of drugs and works by stopping the making of protein by certain bacteria. Spectinomycin was discovered in 1961. It is on the World Health Organization's List of Essential Medicines. It is not available in the United States for human use. It is made from the bacterium Streptomyces spectabilis. Medical uses It is given by intramuscular injection to treat gonorrhea, especially in patients who are allergic to penicillins. This antibiotic is no longer available in the United States for human use, but is still available for veterinary use. Side effects Side effects include itching, chills, stomach ache, and red rash. Mechanism of action Spectinomycin binds to the 30S subunit of the bacterial ribosome and interrupts protein synthesis. One form of resistance has emerged in the 16S ribosomal RNA in Pasteurella multocida. Biosynthetic mechanism Biosynthesis of spectinomycin begins similar to all aminoglycosides, with the formation of an inositol ring. The difference is the initial modification that forms the inositol ring of spectinomycin. The process begins with a glucose-6-phosphate (1a), which is oxidized by NAD+ to form a ketone at C2 (2a). This ketone is then formed into a primary amine group through pyridoxal phosphate (PLP) and glutamine transamination (3a). This process is repeated again at C4 to form a second primary amine (4a). Once these two amines are present, the glucose ring is ready to be methylated through two S-adenosyl methionine molecules (5a). With this methylation, the glucose ring is finally ready to be converted into an inositol ring through inositol cyclase (6a). This can then be hydrolyzed to get rid of the phosphate group, making the inositol ring necessary for spectinomycin (7a). While all this happens, an alternate pathway is occurring creating the sugar functional group from a similar starting product. In this pathway, glucose-1-phosphate is used as the starting product (1b). This is converted into a TDP-glucose through TDP synthase (2b). TDP glucose then has the hydroxyl removed from C6 through a hydratase enzyme (3b),