pre-exposure prophylaxis
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What is pre-exposure prophylaxis (PrEP) in medicine?
Pre-exposure prophylaxis (PrEP) is a medication that lowers the risk of HIV (human immunodeficiency virus) infection, the cause of AIDS (acquired immunodeficiency syndrome), when taken before unprotected sex or sharing needles.
The first PrEP drug, a combination of tenofovir and emtricitabine (Truvada), was approved by the FDA in 2012. PrEP can reduce the risk of HIV infection by about 99% for sexually acquired infection and by 74% for shared needle use among those who inject drugs, when taken consistently in combination with safe sex practices.
PrEP drugs work by preventing HIV from entering immune cells and replicating. Oral medications include Truvada and Descovy, while Apretude is an injectable suspension. PrEP is generally covered by insurance and is considered safe, with minor side effects.
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Why do people use PrEP?
People use pre-exposure prophylaxis (PrEP) medications to lower the risk of HIV infection before potential exposure through unprotected sex or shared needles. Approved by the FDA in 2012, PrEP combines antiretroviral drugs like tenofovir and emtricitabine (Truvada) and is used with safe sex practices.
When taken consistently, PrEP can be highly effective, reducing the risk of HIV infection by about 99% for sexually acquired infections and by 74% for shared needle use among those who inject drugs. PrEP drugs inhibit HIV replication, preventing the virus from entering immune cells.
It's available through insurance and sometimes at no cost, such as via the Ready, Set, PrEP program in the United States. While PrEP is considered safe, it does not protect against other sexually transmitted infections, so condom use is still recommended.
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How does PrEP help prevent disease?
Pre-exposure prophylaxis (PrEP) is a medication taken to lower the risk of HIV infection before potential exposure. PrEP drugs inhibit HIV replication; when taken consistently, they reach optimal levels, preventing HIV from entering immune cells and replicating if exposure occurs.
When used consistently, PrEP can reduce the risk of HIV infection from sexual activity by about 99% and from shared needles by 74%. High PrEP activity helps clear HIV from the body more efficiently by more effectively blocking HIV replication.
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What diseases can PrEP protect against?
Pre-exposure prophylaxis (PrEP) is a medication that can lower the risk of HIV (human immunodeficiency virus) infection, which causes AIDS (acquired immunodeficiency syndrome). PrEP drugs inhibit HIV replication, preventing the virus from entering immune cells and replicating upon exposure.
When taken consistently, PrEP reduces the risk of HIV infection by about 99% for sexually acquired infections and by 74% for those who share needles while injecting drugs. However, PrEP does not protect against other sexually transmitted infections like chlamydia, gonorrhea, or syphilis.
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Who should consider taking PrEP?
Pre-exposure prophylaxis (PrEP) is a medication taken to lower the risk of HIV infection. PrEP is for HIV-negative individuals at high risk of exposure to HIV through unprotected sex or shared needles. When taken consistently, PrEP reduces the risk of HIV infection by about 99% for sexually acquired infections and by 74% for those who inject drugs.
PrEP is generally safe, with mostly minor side effects; however, it only protects against HIV and not other STIs. It is available for free to those who are eligible in the United States through the Ready, Set, PrEP program. PrEP drugs work by inhibiting HIV replication, preventing it from entering immune cells.
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What are some possible side effects or challenges of using PrEP?
PrEP is generally safe, but some individuals may experience side effects when using pre-exposure prophylaxis. Some common side effects include headaches and nausea, which usually subside within weeks. In rare cases, those over 40, or who have diabetes or other conditions, may experience reduced kidney function.
While PrEP prevents HIV, it does not protect against other STIs. Those who use PrEP without condoms have a higher risk of contracting chlamydia, gonorrhea, or syphilis. The effectiveness of PrEP is influenced by adherence to taking the medication consistently.
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pre-exposure prophylaxis (PrEP), medication taken prior to having unprotected sex or sharing needles that helps lower the risk of becoming infected with HIV (human immunodeficiency virus), the cause of AIDS (acquired immunodeficiency syndrome).
The U.S. Food and Drug Administration (FDA) approved the first PrEP drug—an agent that combines the antiretroviral drugs tenofovir and emtricitabine (a combination marketed as Truvada)—in 2012. The drug is used in combination with safe sex practices to help reduce the risk of sexually acquired HIV infection among high-risk HIV-negative individuals. When taken consistently, it has proved to be highly effective, reducing HIV infection risk by about 99 percent in the case of sexually acquired infection and by 74 percent for shared needle use among those who inject drugs.
Underlying mechanisms
PrEP drugs typically work by inhibiting the replication of HIV. When the drugs are taken consistently, their activity levels gradually increase and ultimately become optimal for prophylaxis. At these high, optimal levels, PrEP drugs prevent HIV from entering immune cells and replicating, in the event of exposure to the virus. It is thought that high PrEP activity, in more efficiently blocking HIV replication, further allows for accelerated HIV clearance from the body. The effectiveness of PrEP, however, is influenced by various factors, including drug concentration, the length of time the drugs are taken prior to possible exposure, and patient adherence to taking the medication.
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PrEP drug characteristics
PrEP drugs are available in oral and injectable forms. Oral medications include Truvada and Descovy, the trade name for a combination drug consisting of emtricitabine and tenofovir alafenamide that was approved by the FDA in 2019 for use in individuals at risk of HIV exposure from non-vaginal sex. Both Truvada and Descovy are taken once daily. Apretude, whose active component is an antiretroviral agent known as cabotegravir, is an injectable suspension. A single injection of it is given in each of the first two months of treatment, followed by subsequent injections at two-month intervals.
Availability and side effects
PrEP is generally covered by insurance and in some places is available without insurance and at no cost. In the United States, for example, PrEP is free through the Ready, Set, PrEP program. Participation in the program requires that individuals are U.S. residents, are uninsured, are HIV-negative, and have a prescription for PrEP. In other countries, PrEP may be available at no cost through trials, pilot projects, and certain public agencies.
PrEP is considered to be safe, and its side effects are often minor. Initial use, for example, may cause headache and nausea, which typically resolve within a few days or weeks. In rare instances, individuals who are aged 40 or older or who are affected by diabetes or certain other conditions may experience reductions in kidney function.
PrEP is frequently taken without concomitant condom use. However, PrEP drugs do not protect against the transmission of other sexually transmitted infections (STIs). Thus, individuals who choose to use PrEP in the absence of condoms may be at increased risk of contracting other STIs, particularly chlamydia, gonorrhea, or syphilis.
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