Spectinomycin is an antibiotic originally obtained from the funguslike bacterium Streptomyces spectabilis; it is now mainly produced synthetically. It is especially useful for treating penicillin-resistant strains of gonorrhea, and it may be given to people who are allergic to penicillins, cephalosporins, or probenecid. Spectinomycin sulfate is also frequently used to treat dairy cows and other livestock.
This antibiotic is usually given by injection into muscle tissue and is sold under brand names such as Trobicin. Major side effects include dizziness, chills, itching, and stomach cramps.
This writeup is based on work I did for the science dictionary at http://biotech.icmb.utexas.edu/