Betamethasone + Clindamycin + Nicotinamide is a combination of three medicines : Betamethasone, Clindamycin, and Nicotinamide. Betamethasone is a steroid which works by blocking the production of certain chemical messengers in the body that cause inflammation (redness and swelling) and allergies. Clindamycin is an antibiotic. It works by preventing synthesis of essential proteins required by bacteria to carry out vital functions. Thus, it stops the bacteria from growing, and prevents the infection from spreading. Nicotinamide is a form of vitamin B that provides essential nutrients.