Medications That Prevent HIV Infection

Published: January 06, 2022
Rachel Crusius
By Rachel Crusius, Pharm.D. Candidate 2022

Human immunodeficiency virus (HIV) is a virus that affects your body’s immune system. It is spread from contact with infected bodily fluids such as blood or semen, which can happen via sex or from sharing needles. It also can be passed from mother to infant during childbirth or breastfeeding. If left untreated, HIV can progress to a severe form known as Acquired Immunodeficiency Syndrome (AIDS), where the immune system becomes badly damaged and is unable to fight off severe infections, which can ultimately result in death.

There is no cure for HIV, but it can be controlled by medications. Certain medication combinations are available to reduce your chances of getting HIV. Your pharmacist can play an important role in providing HIV testing and education about symptoms, prevention, and treatment options.

How do I protect myself from getting HIV?

There are many ways to protect yourself from getting HIV. You can use strategies such as never sharing needles, abstinence from sex (not having sex), limiting the number of sexual partners you have, or using condoms correctly each time you do have sex.


There are also medications that prevent you from getting HIV called pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP). These preventative medications can be taken before or after HIV exposure to reduce your risk of being infected.


Who should use preventative medications?

PrEP is a prevention strategy for individuals who do not have HIV and are at risk for being exposed to the virus through sexual contact or injectable drug use. If taken as prescribed, PrEP medications can work very well at keeping people from getting infected with HIV.


PEP is a prevention strategy for individuals who do not have HIV but were exposed once during a single high-risk incident, such as contact with infected blood or semen from an infected individual. PEP medications, usually a combination of three drugs, must be taken within 72 hours of the exposure and continued for 4 weeks.


What are the preventative medications?

There are three PrEP medications approved for HIV prevention:


Truvada can be used to prevent HIV in females and males at risk for HIV infection through sexual contact or injectable drug use. Descovy can be used to prevent HIV in males at risk for HIV infection through sexual contact or injectable drug use but is limited for use in females at risk for HIV infection through injectable drug use only. Apretude or Vocabria can be used to prevent HIV in males or females at risk of HIV infection through sexual contact.


If taken or used exactly as prescribed, PrEP can reduce your risk of getting HIV from sex by 99% and by at least 74% in people who inject drugs, according to the Centers for Disease Control and Prevention. If not taken as prescribed, PrEP will not work as well.


There are many combinations of PEP medications available. Talk to your doctor as soon as you can after a high-risk exposure incident so they can prescribe the best combination of medications for you.


How do I take preventative medications?

 PrEP and PEP medications are available by prescription only.


Truvada and Descovy come in the form of a tablet that is taken by mouth once a day. Truvada and Descovy do not provide protection right away; they must be taken daily for 7 days before receptive anal sex (bottoming), and 21 days before receptive vaginal sex or injection use, before it is fully effective. It is unknown how long it should be taken before fully effective for insertive vaginal sex or insertive anal sex.


Apretude comes as an injection given as a single shot in the buttocks by a doctor or nurse every month and then every other month after that. Vocabria, a tablet form of Apretude that is taken by mouth once daily, may be given for 28 days prior to the Apretude shot to make sure that you tolerate the medicine well. It is uncertain how long Apretude needs to be used before it provides the most protection.


PEP medications must be taken within 3 days of exposure to be effective and continued to be taken for 4 weeks.


In order for PrEP and PEP medications to be as effective as possible, they should be taken as part of a regular schedule. Medications by mouth should be taken at about the same time every day. The Apretude shot should be given at regular scheduled intervals. Try not to miss any appointments with your doctor.



HIV causes a chronic infection requiring daily medication to stop progression to AIDS and potential death. If you are at risk for HIV infection from sexual contact, use prevention strategies such as reducing your number of partners and using condoms correctly but also, talk to your doctor about whether PrEP may be right for you. If you inject drugs, then avoid sharing needles and practice safe sex with condom use and talk to your doctor about PrEP medications.


If you have a high-risk incident, be sure to ask your doctor about PEP medications right away.


If you use a PrEP or PEP medication, be sure to take it correctly and don’t stop without first talking to your doctor or pharmacist.

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