What is the recommended regimen for HIV (Human Immunodeficiency Virus) pre-exposure prophylaxis (PrEP)?

Recommended Regimens for HIV Pre-Exposure Prophylaxis (PrEP)

Tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) once daily is the primary recommended regimen for HIV pre-exposure prophylaxis (PrEP) for all individuals at risk of HIV infection. 1

Primary PrEP Recommendations

Standard Daily Oral PrEP

• TDF 300mg/FTC 200mg as a single daily oral pill is the standard recommended regimen for all populations at risk for HIV acquisition 1
• For men who have sex with men (MSM), a double dose (2 pills) of TDF/FTC is recommended on the first day of PrEP initiation to achieve protective drug levels more quickly 1
• PrEP should be initiated as soon as feasible for individuals who have chosen to use it 1

Alternative PrEP Options

• For MSM with or at risk for kidney dysfunction, osteopenia, or osteoporosis, daily tenofovir alafenamide/emtricitabine (TAF/FTC) is recommended 1
• For MSM and transgender women, event-driven PrEP using the "2-1-1" method (two tablets taken 2-24 hours before sex, followed by one tablet 24 hours after the first dose and another tablet 24 hours later) is an effective alternative to daily dosing 1
• Injectable cabotegravir every 8 weeks is recommended (pending regulatory approval) as PrEP for cisgender men and transgender women who have sex with men 1

Populations for Whom PrEP is Recommended

PrEP is recommended for individuals at high risk of HIV acquisition, including:

• Men who have sex with men (MSM) with any of the following: condomless anal sex in past 6 months, multiple partners, or high risk score on validated assessment tools 1
• Transgender women, especially those engaging in high-risk sexual behaviors 1
• Heterosexual serodiscordant couples (where one partner has HIV and the other does not) 1
• People who inject drugs and share injection equipment 1
• At-risk heterosexual men and women with high-risk sexual behaviors 1

Pre-Initiation Assessment

Before starting PrEP, the following tests are essential:

• Combined HIV antibody and antigen testing (with HIV RNA testing if acute infection is suspected) 1
• Serum creatinine level to assess kidney function 1
• Hepatitis B surface antigen testing 1
• Hepatitis C antibody testing 1
• Hepatitis A antibody testing for MSM and people who inject drugs 1
• Genital and non-genital testing for sexually transmitted infections 1

Monitoring During PrEP Use

• At 1 month after initiation: Combined HIV antibody and antigen test 1
• Every 3 months:
  • HIV testing to ensure the patient remains HIV-negative 1
  • Screening for sexually transmitted infections 1
• Every 6 months:
  • Creatinine assessment to monitor kidney function 1
  • More frequent monitoring may be needed for patients with risk factors for kidney disease 1

Important Considerations and Potential Pitfalls

• Adherence is critical: The effectiveness of PrEP is directly correlated with adherence; poor adherence significantly reduces protection 2
• Rule out acute HIV infection: PrEP should not be initiated until HIV RNA test results confirm uninfected status, especially if there are symptoms consistent with acute HIV infection 1
• Drug resistance risk: Starting PrEP in someone with undiagnosed HIV infection can lead to drug resistance; this is rare (<0.1%) but highlights the importance of proper HIV testing before initiation 2, 3
• Kidney function: TDF can affect kidney function, so regular monitoring is essential, particularly in those with existing kidney issues 1
• Bone density: TDF may cause small decreases in bone mineral density; TAF/FTC may be preferred for those with osteopenia or osteoporosis 1
• Hepatitis B: Caution is needed when using PrEP in patients with chronic hepatitis B due to risk of hepatitis flares if PrEP is discontinued 1

Special Populations

• Women: PrEP offers women a discreet prevention method that doesn't require partner consent. Daily dosing (not event-driven) is recommended for women as pharmacokinetic data suggests less consistent drug levels in vaginal tissues with intermittent dosing 1, 4
• Transgender individuals: Limited data exists on interactions between PrEP and hormone therapy, but PrEP is still recommended for at-risk transgender people 1
• People who inject drugs: Daily oral TDF/FTC has shown effectiveness in this population 1

PrEP is a highly effective HIV prevention strategy when used correctly and consistently, with efficacy exceeding 90% in adherent individuals 2, 5.