Pre-exposure prophylaxis

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PrEP, an acronym from Pre-Exposure Prophylaxis, is the use of prescription drugs by people who do not have HIV/AIDS as a strategy for the prevention of HIV/AIDS. It is an optional treatment which may be taken by people who are HIV negative, but who have substantial, higher-than-average risk of contracting an HIV infection.

Currently, the only drug which any health organization recommends for PrEP is Truvada, which is the brand name of the Gilead Sciences drug combination of Tenofovir/emtricitabine. The Centers for Disease Control says that "PrEP is a powerful HIV prevention tool and can be combined with condoms and other prevention methods to provide even greater protection than when used alone. But people who use PrEP must commit to taking the drug every day and seeing their health care provider for follow-up every 3 months."[1]

PrEP is intended for use with condoms. Contrary to all medical advice, PrEP is sometimes used by those who do not wish to use condoms and who intend to have bareback sex. There are social groups which both support and oppose the use of PrEP.

Medical uses[edit]

the clinical practice guideline for PrEP published by the Centers for Disease Control

In the United States, federal guidelines recommend the use of PrEP for HIV negative people with the following characteristics:

  • in a serodiscordant sexual relationship, meaning that the HIV-negative person regularly has sex with an HIV positive person[1]
  • anyone who is not in a monogamous relationship with an HIV negative person, and who...
  • has shared recreational drug injection equipment with other drug users, or who has been in treatment for injection drug use in the past six months[1]

Reasons to avoid[edit]

Reasons for not using PrEP include the following:

  • Persons with HIV should never use PrEP, and an HIV test is necessary before starting to use PrEP[2]
  • persons with kidney problems, especially decreased renal functions, have increased safety problems with using PrEP[2]
  • persons with hepatitis B have increased safety problems with using PrEP[2]
  • women who are pregnant or breastfeeding should speak with their doctors about potential risk to their children[2]
  • Minors may not have access to services which complement the effective use of PrEP, and need extra attention from their doctor if they use PrEP[2]

Adverse effects[edit]

The PrEP studies have shown the drugs to be safe, with few side effects. Generally, minor side effects such as nausea or diarrhea resolve themselves within the first few months.[3] Any deleterious effect of Truvada on kidney function usually reverses with drug discontinuation,[4] but irreversible kidney damage can rarely occur.[citation needed]


The terms "pre-exposure prophylaxis" or "PrEP" most commonly refer to an HIV-prevention strategy where antiretrovirals are used to protect HIV-negative people from HIV infection. The HIV antiviral Truvada was approved by the FDA for PrEP on 16 July 2012.[5] The CDC amended its guidelines for HIV prevention recommending pre-exposure prophylaxis with Truvada to high infection risk populations on 14 May 2014,[6] due to research indicating prophylactic effectivity preventing transmission from mother to child.[7] Prior to that date, Truvada was only approved to treat existing HIV infections.

PrEP has been gaining a lot of attention and focus, especially within the battle against AIDS in New York City, a metropolis known for the epidemic's fatality. Governor Andrew Cuomo of New York has pledged his battle to end AIDS by 2020. According to a New York Times article, Cuomo intends to dramatically drop the infection number to 750 by 2020 from about 3000 in 2013 and 14,000 in 1993. In a city that has a large gay population, Cuomo intends to target his gay male audience. In addition to the use of condoms, Cuomo hopes that PrEP will continue to reduce the number of infections. However, the drug has met some sort of resistance as users may be noted as "Truvada whores," or people who miss their daily uptake of the drug and still do not use a condom. Overall, the fight against HIV infection seems to be going strong. Infection rates have fallen 28% overall from 2007 to 2012.[8]


Most PrEP studies utilize the drug tenofovir or a tenofovir/emtricitabine combination (Truvada) that is delivered orally. Initial studies of PrEP strategies in non-human primates showed a reduced risk of infection among animals that receive ARVs prior to exposure to a simian form of HIV. A 2007 study at UT-Southwestern (Dallas) and the University of Minnesota showed PrEP to be effective in "humanized" laboratory mice.[9] In 2008, the iPrEx study demonstrated 42% reduction of HIV infection among men who have sex with men,[10] and subsequent analysis of the data has suggested that 99% protection is achievable if the drugs are taken every day.[11]

PrEP approaches with agents besides oral Truvada are currently in clinical trials not listed here.[citation needed]

Study Type of PrEP Study Population Findings
CAPRISA 004 Pericoital tenofovir gel South African females 39% reduction of HIV infection[12]
iPrEx Oral emtricitabine/tenofovir Men who have sex with men 42% reduction of HIV infection.[10] 99% reduction estimated with daily adherence[11]
Partners PrEP Oral emtricitabine/tenofovir; oral tenofovir African heterosexual couples 73% and 62% reduction of infection[7]
TDF2 Oral emtricitabine/tenofovir Botswana heterosexual couples 63% reduction of infection[3]
FEM-PrEP Oral emtricitabine/tenofovir African females No reduction (study halted due to low adherence)
VOICE 003 Oral emtricitabine/tenofovir; oral tenofovir; vaginal tenofovir gel African females No reduction in oral tenofovir or vaginal gel arms [oral emtricitabine/tenofovir arm ongoing][3]
Bangkok Tenofovir Study Oral tenofovir Thai male injection drug users 48.9% reduction of infection[13]
ANRS - Ipergay Oral emtricitabine/tenofovir French gay males 86% reduction of infection[14]

See also[edit]


  1. ^ a b c d e f g Centers for Disease Control (30 September 2014). "CDC - Pre-Exposure Prophylaxis (PrEP)". Retrieved 28 December 2014. 
  2. ^ a b c d e United States Public Health Service. "Preexposure Prophylaxis for the Prevention of HIV Infection in the United States - 2014". Centers for Disease Control and Prevention. 
  3. ^ a b c Celum, CL (December 2011). "HIV preexposure prophylaxis: new data and potential use.". Topics in antiviral medicine 19 (5): 181–5. PMID 22298887. 
  4. ^
  5. ^ "FDA approves first drug for reducing the risk of sexually acquired HIV infection". Retrieved 28 February 2015. 
  6. ^ "CDC - Pre-Exposure Prophylaxis (PrEP) - Research - Prevention Research - HIV/AIDS". Retrieved 28 February 2015. 
  7. ^ a b Celum C, Baeten JM (February 2012). "Tenofovir-based pre-exposure prophylaxis for HIV prevention: evolving evidence". Curr. Opin. Infect. Dis. 25 (1): 51–7. doi:10.1097/QCO.0b013e32834ef5ef. PMC 3266126. PMID 22156901. 
  8. ^ Barro, Josh. "Pill to Prevent H.I.V. Gets a Prominent Backer: Andrew Cuomo". NYTimes.Com. New York Times. Retrieved 30 November 2014. 
  9. ^ Denton PW, Estes JD, Sun Z et al. (January 2008). "Antiretroviral pre-exposure prophylaxis prevents vaginal transmission of HIV-1 in humanized BLT mice". PLoS Med. 5 (1): e16. doi:10.1371/journal.pmed.0050016. PMC 2194746. PMID 18198941. 
  10. ^ a b Grant RM, Lama JR, Anderson PL et al. (December 2010). "Preexposure chemoprophylaxis for HIV prevention in men who have sex with men". N. Engl. J. Med. 363 (27): 2587–99. doi:10.1056/NEJMoa1011205. PMC 3079639. PMID 21091279. 
  11. ^ a b "PrEP: PK Modeling of Daily TDF/FTC (Truvada) Provides Close to 100% Protection Against HIV Infection". Retrieved 28 February 2015. 
  12. ^ Andrei G, Lisco A, Vanpouille C et al. (October 2011). "Topical tenofovir, a microbicide effective against HIV, inhibits herpes simplex virus-2 replication". Cell Host Microbe 10 (4): 379–89. doi:10.1016/j.chom.2011.08.015. PMC 3201796. PMID 22018238. 
  13. ^ Choopanya K, Martin M et al. (June 2013). "Antiretroviral prophylaxis for HIV infection in injecting drug users in Bangkok, Thailand (the Bangkok Tenofovir Study): a randomised, double-blind, placebo-controlled phase 3 trial". The Lancet 381 (9883): 2083–2090. doi:10.1016/S0140-6736(13)61127-7. PMID 23769234. 
  14. ^ Gilles Pialoux. "Ipergay : La Prep «à la demande», ça marche fort (quand on la prend).". 

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