PrEP is short for Preexposure Prophylaxis and is the use of antiretroviral medication to prevent HIV infection before it occurs. 

PrEP is a medication that is prescribed to people who do not actively have HIV but are at a high risk for getting it through sexual contract or IV drug use. 

Side effects include upset stomach, mild headache and loss of appetite that usually will resolve after 1 month. There are no reported serious side effects and considered generally safe. 

Multiple Studies have demonstrated when taken as prescribed and consistently everyday it is 99% effective protecting you from sexual contact exposure and 74-84% effective protecting you from IV drug use exposure. You are considered protected after taking the medication for at least 7 days for anal intercourse and 21 days for vaginal intercourse or IV drug use. 

PrEP Treatment does not protect you from other STDs so you still want to protect yourself by using condoms or other barrier contraceptives and to get tested frequently. 

You will need to have blood tests to check for HIV and other STDs as well as kidney function. Your health insurance should cover the cost of the medication but in the event it does not there are several state drug assistance programs.