Chemoprophylaxis

Chemoprophylaxis, also called chemoprevention, is the administration of a medication to prevent disease or infection before it occurs, rather than to treat an existing illness. Antibiotics are a common example, given to immunocompromised patients to guard against bacterial infection or to otherwise healthy people during a disease outbreak to limit its spread, and the approach is also used to prevent recurrent infections, such as repeated urinary tract infections, and to keep a localized infection from spreading to other organ systems. Its use is limited chiefly by two factors: the medication's side effects may outweigh the preventive benefit, and the cost of treating a whole population can be impractical when the underlying disease is rare or the drug itself is expensive.