Definition: Antiretroviral therapy, also known as antiviral drugs, is used to treat or prevent HIV from entering people's immune systems. It targets and eliminates viral RNA in the body, thus stopping its replication. Antiretrovirals help reduce virus load by preventing it from crossing the blood-brain barrier to the brain. Definition: The act of using a drug designed to inhibit the action of an antiviral drug to prevent the virus from causing damage to the immune system and spread through the bloodstream; in this case, antiretroviral therapy.