What is HIV Pre-Exposure Prophylaxis (PrEP)?

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Last updated: May 14, 2025View editorial policy

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From the Guidelines

PrEP is recommended for individuals at risk for HIV infection, with tenofovir disoproxil fumerate/emtricitabine once daily being the preferred oral PrEP regimen 1. The use of PrEP has been shown to be highly effective in preventing HIV infection in people at risk, with a significant reduction in HIV acquisition observed in clinical trials 1.

Key Recommendations for PrEP

  • Tenofovir disoproxil fumerate/emtricitabine once daily is recommended for oral PrEP 1
  • For men who have sex with men (MSM), a double dose (2 pills) of tenofovir disoproxil fumerate/emtricitabine is recommended on the first day 1
  • Oral PrEP dosing using the 2-1-1 (or on-demand) method is recommended only for MSM 1
  • Injectable cabotegravir every 8 weeks is recommended (pending approval by regulatory agencies and availability) as PrEP for cisgender men and transgender women who have sex with men 1

Important Considerations

  • PrEP requires regular medical follow-up every 3 months for HIV testing, STI screening, and kidney function monitoring
  • Side effects are generally mild and may include nausea, headache, or fatigue, typically resolving within the first month
  • PrEP works by maintaining sufficient levels of antiretroviral medication in the bloodstream and tissues to prevent HIV from establishing infection if exposure occurs
  • It's essential to note that PrEP only protects against HIV, not other sexually transmitted infections, so condom use is still recommended for comprehensive protection 1

From the Research

HIV Pre-Exposure Prophylaxis (PrEP)

  • PrEP is a highly effective method for preventing HIV transmission, with studies showing that daily dosing of tenofovir disoproxil fumarate (TDF)/emtricitabine can reduce HIV acquisition by more than 90% 2, 3.
  • The efficacy of PrEP is highly correlated with adherence, and regular monitoring is necessary to ensure optimal adherence and minimize the risk of adverse effects 2, 4.
  • PrEP is recommended for individuals at high risk of acquiring HIV, including men who have sex with men, high-risk heterosexuals, and injection drug users who share injection equipment 2, 4.

Safety and Tolerability

  • TDF/emtricitabine is generally safe and well-tolerated, with fewer than 2% of individuals discontinuing PrEP due to adverse effects 2.
  • Common adverse effects include nausea, abdominal pain, headache, and increased creatinine 4.
  • Resistance to TDF/emtricitabine is rare, but can occur in individuals with undiagnosed acute HIV infection 2.

Real-World Implementation

  • Despite its efficacy, PrEP is underutilized, with fewer than 20% of eligible individuals in the United States using PrEP 2.
  • Barriers to PrEP use include lack of awareness, high cost, and concerns about adherence and resistance 5, 6.
  • New PrEP agents and technologies are being developed to address these challenges and expand access to PrEP, including novel oral agents, long-acting injectables, and multipurpose technologies 6.

Clinical Practice

  • Primary care providers play a critical role in implementing PrEP, and guidelines and toolkits are available to support PrEP prescription and monitoring 4.
  • Regular office visits are necessary to ensure adherence, provide ongoing counseling, and monitor for side effects 4.
  • Pharmacists can also play a key role in optimizing PrEP implementation and addressing barriers to access 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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