PrEP, or Pre-Exposure Prophylaxis, is a medication that prevents HIV infection in people who are HIV-negative but at high risk of exposure to the virus. When taken as prescribed, PrEP reduces the risk of getting HIV from sex by about 99% and from injection drug use by at least 74%. This daily pill works by establishing a presence of medication in the bloodstream that can stop HIV from taking hold and spreading throughout the body.
HIV prevention has evolved significantly over the decades, with PrEP representing one of the most significant advances in this field. The medication contains antiretroviral drugs similar to those used to treat HIV, but instead works preventatively. PrEP does not protect against other sexually transmitted infections or pregnancy, so combining it with condoms and regular testing provides comprehensive protection.
Healthcare providers can help determine if PrEP is right for you based on your risk factors and lifestyle. Regular follow-up appointments are necessary to monitor for side effects and ensure continued HIV-negative status while using this prevention method.
Understanding Pre-Exposure Prophylaxis (PrEP)
Pre-Exposure Prophylaxis represents a significant advancement in HIV prevention strategy, offering protection before potential exposure occurs. This medication-based approach has proven highly effective when taken as prescribed, with several FDA-approved options now available to suit different needs.
What Is PrEP?
Pre-Exposure Prophylaxis (PrEP) is a preventive medication taken by HIV-negative individuals to reduce their risk of acquiring HIV. Unlike post-exposure treatments, PrEP works proactively by establishing a protective presence in the bloodstream before any potential exposure to the virus.
PrEP is recommended for people at higher risk of HIV infection, including men who have sex with men, transgender individuals, people with HIV-positive partners, and those who share injection equipment. When taken daily or as prescribed, PrEP creates a shield that prevents HIV from establishing infection in the body.
Healthcare providers typically perform HIV testing, kidney function assessment, and STI screening before prescribing PrEP. Regular follow-up appointments are essential to monitor for side effects and ensure continued effectiveness.
The Effectiveness of PrEP
Studies have demonstrated that PrEP reduces the risk of HIV infection by approximately 99% when taken as prescribed. This remarkable effectiveness rate applies to sexual transmission prevention when the medication reaches optimal levels in the bloodstream.
For people who inject drugs, PrEP can reduce HIV risk by at least 74%. The protection level directly correlates with adherence—consistent daily use provides maximum protection, while irregular use significantly reduces effectiveness.
PrEP does not protect against other sexually transmitted infections or pregnancy. Using condoms alongside PrEP provides comprehensive protection against multiple STIs and unwanted pregnancy.
Real-world implementation has shown dramatic reductions in new HIV infections in communities where PrEP use is widespread. Many cities with robust PrEP programs have reported declining HIV rates among at-risk populations.
PrEP Medications: Truvada, Descovy, and Apretude
Truvada was the first FDA-approved PrEP medication, combining tenofovir disoproxil fumarate and emtricitabine. It’s approved for all groups at risk for HIV and is available as a generic, making it more affordable for many patients.
Descovy contains tenofovir alafenamide instead of tenofovir disoproxil fumarate, potentially offering less impact on bone density and kidney function. However, Descovy is not approved for those at risk through receptive vaginal sex as studies haven’t confirmed its effectiveness in this group.
Apretude (cabotegravir) represents the newest option—an injectable PrEP administered every two months. This long-acting formulation eliminates daily pill requirements and may help those struggling with medication adherence.
Each medication has specific considerations regarding side effects, cost, and insurance coverage. Many patients can access these medications through insurance programs, patient assistance programs, or specialized clinics.
How PrEP Works in HIV Prevention
Pre-exposure prophylaxis (PrEP) represents a significant advancement in HIV prevention through its targeted biochemical approach. The medication works by establishing a protective barrier in the bloodstream that prevents HIV from establishing infection in the body.
The Role of Antiretroviral Medications
PrEP medications contain antiretroviral drugs—the same class of medications used to treat HIV infection. The most common PrEP formulations contain tenofovir and emtricitabine, which work as nucleoside reverse transcriptase inhibitors (NRTIs).
These medications block an enzyme called reverse transcriptase that HIV needs to replicate itself in the body. By inhibiting this crucial step in the virus’s life cycle, PrEP prevents HIV from establishing a permanent infection.
When taken consistently, these antiretroviral medications maintain sufficient drug levels in the bloodstream and tissues to provide protection. Different PrEP formulations require different dosing schedules to maintain effective drug levels.
Available PrEP Medications:
- Truvada (tenofovir disoproxil fumarate/emtricitabine)
- Descovy (tenofovir alafenamide/emtricitabine)
- Apretude (cabotegravir) – injectable form
Preventing HIV Transmission
PrEP creates a biochemical shield that prevents HIV from establishing infection during exposure. When someone is exposed to HIV—whether through sexual contact or sharing injection equipment—the virus cannot complete its replication process if PrEP is present.
For optimal protection, PrEP must reach sufficient concentration in the bloodstream before potential exposure. Daily oral PrEP typically requires 7 days of consistent use to reach protective levels for receptive anal sex, and up to 21 days for other exposure routes.
The protective effect remains only while medication levels stay adequate in the body. If doses are missed or the medication is discontinued, protection diminishes relatively quickly.
PrEP does not prevent other sexually transmitted infections or pregnancy. It specifically targets HIV and works independently of condoms or other prevention methods.
Reduction of HIV Risk in High-Risk Populations
PrEP has demonstrated remarkable effectiveness across several groups at elevated risk for HIV acquisition. When taken as prescribed, it reduces HIV transmission risk by approximately 99% during sexual contact.
Key populations who benefit from PrEP include:
- Men who have sex with men
- Transgender individuals
- People with sexual partners living with HIV
- Individuals with multiple sexual partners
- People who inject drugs
For individuals who have a sexual partner with HIV, PrEP provides crucial protection, especially when the partner has a detectable viral load. Similarly, those engaging in injection drug use can significantly reduce transmission risk through consistent PrEP use.
Risk reduction varies based on adherence, with studies showing that strict medication compliance correlates directly with higher levels of protection. Even with occasional missed doses, PrEP still offers substantial protection compared to no prevention method.
Administering and Monitoring PrEP
Proper administration and regular monitoring are crucial components of an effective PrEP regimen. Healthcare professionals follow established protocols to ensure patients receive appropriate dosing, testing, and support throughout their treatment.
PrEP Dosage and Administration
PrEP is typically prescribed as a once-daily oral tablet containing tenofovir disoproxil fumarate and emtricitabine (Truvada) or tenofovir alafenamide and emtricitabine (Descovy). The medication must be taken consistently to maintain protective drug levels in the bloodstream.
For cisgender men who have sex with men, “2-1-1” or “on-demand” dosing may be an option. This involves taking two pills 2-24 hours before sexual activity, followed by one pill 24 hours later and another 48 hours after the initial dose.
It takes approximately 7 days of daily use for PrEP to reach maximum protection in rectal tissue and about 21 days for vaginal tissue. Healthcare providers often recommend using additional protection methods during this initial period.
Regular Health Care Provider Visits
Before starting PrEP, patients must receive a negative HIV test to ensure they are not already infected. Initial screenings also include tests for other STIs, hepatitis B, and kidney function assessment.
Follow-up visits typically occur every three months and include:
- HIV testing to confirm continued negative status
- STI screening and treatment if necessary
- Kidney function monitoring
- Discussion about adherence challenges
- Assessment of continued HIV risk factors
- Pregnancy testing for those who may become pregnant
These regular visits help healthcare providers identify any issues early and adjust treatment as needed. Missing appointments can result in interrupted prescriptions, potentially reducing PrEP’s effectiveness.
Managing Side Effects and Risks
Most people tolerate PrEP well, but some may experience mild side effects that typically resolve within the first month. Common side effects include:
- Nausea or stomach discomfort
- Headache
- Dizziness
- Weight loss
About 10% of patients report these symptoms initially. If side effects persist or worsen, patients should consult their healthcare provider rather than discontinuing treatment independently.
Long-term monitoring focuses on kidney function and bone density, as PrEP may affect these in some individuals. Regular communication with healthcare providers helps address concerns promptly and ensures continued protection.
Patients should inform their sexual partners about their PrEP use as part of comprehensive sexual health discussions, though this remains a personal choice.
Frequently Asked Questions
PrEP therapy involves several important considerations regarding eligibility, effectiveness, access, and potential health impacts. Below are answers to common questions that individuals may have when considering this HIV prevention method.
Who should consider taking PrEP for HIV prevention?
PrEP is recommended for individuals at substantial risk of HIV infection. This includes people who have sexual partners with HIV, men who have sex with men and engage in condomless sex, individuals who don’t consistently use condoms, and people who share injection equipment.
People with multiple sexual partners or those in high-prevalence communities should also consider PrEP. Healthcare providers can help determine if someone’s risk factors warrant PrEP therapy.
Is it possible to contract HIV from an individual who is undergoing PrEP therapy?
If someone is taking PrEP consistently as prescribed, the risk of transmitting HIV is extremely low. PrEP is highly effective when taken properly, reducing the risk of HIV acquisition by about 99% during sexual contact.
However, PrEP doesn’t protect against other sexually transmitted infections. It’s important to remember that PrEP works best when combined with other prevention methods like condoms.
What are the locations where one can obtain a prescription for PrEP?
PrEP can be prescribed by primary care physicians, infectious disease specialists, and healthcare providers at sexual health clinics. Many community health centers and LGBTQ+ focused clinics also provide PrEP services.
Specialized clinics like LocalMD in NYC offer comprehensive PrEP services, including consultation, testing, and prescriptions. Telehealth options have also expanded access to PrEP prescriptions in many regions.
What are the potential side effects associated with taking PrEP medication?
Some people experience mild side effects when starting PrEP, including nausea, headaches, and fatigue. These symptoms typically resolve within the first few weeks of treatment.
More serious concerns include potential kidney function issues and slight decreases in bone mineral density. Regular medical monitoring is required to detect any adverse effects early.
The benefits of HIV prevention generally outweigh these potential side effects for individuals at substantial risk of HIV infection.
How long is it recommended to continue using PrEP following potential HIV exposure?
PrEP is not designed for post-exposure protection. For potential HIV exposures, post-exposure prophylaxis (PEP) is recommended, which should be started within 72 hours of exposure.
For ongoing protection, PrEP should be taken daily or as prescribed by a healthcare provider. When deciding to stop PrEP, individuals should continue taking it for at least 7 days after their last potential HIV exposure.
Healthcare providers can offer guidance on the appropriate duration based on individual circumstances and risk factors.
What are the implications of beginning PrEP if you are already HIV positive?
Starting PrEP when already HIV positive can lead to drug resistance, as PrEP medications alone are insufficient for treating HIV infection. This can complicate future HIV treatment options.
HIV testing is mandatory before starting PrEP and should be repeated regularly during treatment. If someone tests positive for HIV while on PrEP, they should immediately consult their healthcare provider to transition to appropriate HIV treatment.
Early detection of HIV infection is crucial to ensure proper comprehensive treatment rather than the limited medication exposure that PrEP provides.
