PEP stands for post-exposure prophylaxis. It involves taking antiretroviral medicines as soon as possible, but no more than 72 hours (3 days) after you may have been exposed to HIV, to try to reduce the chance of becoming HIV-positive. Though the window is within 72 hours of exposure, the sooner you are able to take the medication after an exposure the better.
You will be asked to take the medication for 28 days. Though these drugs have proven to be effective in preventing HIV for some, there is no guarantee this will work for everyone.
If you are prescribed PEP, you may need to undergo routine HIV testing at four weeks and three to six months after exposure. You may also be asked additional questions about your exposure, the person you were exposed to (in case they can be reached for HIV testing) and to test for other sexually transmitted infections. Women may also be asked to take a pregnancy test. It is also likely, you will discuss how to lower your risk and avoid HIV exposure in the future.
PEP is generally prescribed for people fitting in the following categories:
- A healthcare worker exposed to blood or body fluids of HIV positive patient
- A person who has been sexually assaulted
- A person who has shared needles for drug use, tattooing or hormones with someone either they know to be HIV positive or whose HIV status they do not know
- A person who has engaged in sex without condoms with someone either they know to be HIV positive or whose HIV status they do not know
PEP is for emergency situations when someone may have been exposed to HIV. For someone who is at an ongoing risk for HIV, PrEP is the recommended option.
PEP is effective at preventing HIV when started and taken correctly, but it is not 100%. A person needs to start taking PEP as soon as possible after a potential exposure, but not longer than 72 hours. According to the Centers for Disease Control and Prevention (CDC), research has shown that PEP has little or no effect in preventing HIV infection if it is started later than 72 hours after exposure.
It is also important to take the full course of PEP, as prescribed. PEP is prescribed for 28 days, with medication taken once or twice daily.
PEP is safe, but some people taking PEP have experienced nausea as a side effect.
PrEP stands for pre-exposure prophylaxis. Oral PrEP involves taking a pill once daily to prevent HIV infection in someone who is HIV-negative. Currently there are two pills approved for PrEP: Truvada (for anyone at-risk for HIV) and Descovy (for those at risk except for people assigned female gender at birth who may be at risk for HIV from vaginal sex). When taken consistently, every day, PrEP has been shown to reduce the risk of HIV infection in people who are at high risk by about 99%.
Another PrEP option—Apretude—is given as an injection every two months (following two starter doses given a month apart). This type of PrEP is approved to reduce the risk of sexually acquired HIV in at-risk adults and adolescents weighing at least 77 pounds.
PrEP is a way to prevent HIV infection for those that are at higher risk. The Centers for Disease Control and Prevention (CDC) recommends PrEP for anyone who is in an ongoing relationship with someone who is HIV-positive. Additionally, CDC also suggest PrEP be considered for anyone who isn’t in a mutually monogamous relationship with a partner who recently tested HIV-negative, and
- is a gay or bisexual man who has had anal sex without a condom or have been diagnosed with an STI in the past 6 months.
- is a heterosexual man or woman who does not regularly use condoms with partners with an unknown HIV status who are at substantial risk for HIV infections (e.g. people who inject drugs).
PrEP is also recommended for people who have injected drugs in the past 6 months and have shared injection equipment or have been in treatment for injection drug use in the past 6 months.
When taken consistently, every day, PrEP has been shown to reduce the risk of HIV infection in people who are at high risk by more than 90%.
There have been no significant side effects found in any PrEP trials to date. Some side effects associated with PrEP include an upset stomach, headache, vomiting, and loss of appetite. However, symptoms typically go away after the first month of taking the medication. You should tell your healthcare provider if these or other symptoms become severe or do not go away.
While PrEP can affect kidney function, changes in kidney health are typically modest and are reversible--meaning kidney function is restored when a person stops taking the medication. A healthcare provider will monitor your kidney health regularly while you are taking PrEP.
PrEP is covered by most insurance plans as well as Medicaid. For those that don't have coverage, there are patient assistance programs that can provide financial help to cover the costs of prescriptions.
According to the Centers for Disease Control and Prevention (CDC), PrEP reaches maximum protection from HIV for receptive anal sex at about 7 days of daily use. For all other activities, including insertive anal sex, vaginal sex, and injection drug use, PrEP reaches maximum protection at about 20 days of daily use.
Yes, you should continue using condoms even when you are taking PrEP. If PrEP is taken daily, it offers a lot of protection against HIV infection, but not 100%. Condoms also offer a lot of protection against HIV infection if they are used correctly every time you have sex, but not 100%. PrEP medicines also don't give you any protection from other infections you can get during sex (like gonorrhea, chlamydia, and hepatitis), but condoms do. So you will get the most protection from HIV and other sexually transmitted diseases if you consistently take PrEP medicine and consistently use condoms during sex.