What is the recommended post-exposure prophylaxis (PEP) regimen for a pregnant or non-pregnant woman exposed to Human Immunodeficiency Virus (HIV)?

HIV Post-Exposure Prophylaxis for Women

For both pregnant and non-pregnant women exposed to HIV, initiate bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) 50mg/200mg/25mg as a single tablet once daily for 28 days, starting within 72 hours of exposure (ideally within 24 hours). 1, 2

Preferred Regimen

The first-line PEP regimen is BIC/FTC/TAF (Biktarvy®) taken as one tablet daily for 28 days. 1, 2 This regimen offers:

• Superior renal and bone safety compared to older tenofovir disoproxil fumarate (TDF)-based regimens, which is particularly important for women who may have lower bone density 1, 2
• Single-tablet formulation that significantly improves completion rates—critical since incomplete adherence dramatically reduces effectiveness 1, 2
• Excellent tolerability profile with lower rates of gastrointestinal side effects compared to older regimens 1

Alternative Regimen

If BIC/FTC/TAF is unavailable, use dolutegravir (DTG) 50mg once daily PLUS emtricitabine/tenofovir alafenamide (FTC/TAF) 200mg/25mg once daily for 28 days. 1, 2

• You can substitute tenofovir disoproxil fumarate (TDF) 300mg for TAF if TAF is unavailable, though TAF is strongly preferred due to better renal safety 1, 2
• Lamivudine (3TC) 300mg can substitute for emtricitabine if needed 2

Critical Timing Requirements

Initiate PEP immediately—do not delay the first dose for any reason, including awaiting laboratory results or source patient testing. 1, 2 The efficacy window is:

• Optimal: Within 24 hours of exposure 1, 2
• Maximum: Within 72 hours of exposure—efficacy decreases dramatically with each passing hour 1, 2, 3
• Beyond 72 hours: While guidelines recommend the 72-hour window, for highest-risk exposures with modern well-tolerated regimens, late initiation may still offer some benefit, though efficacy is significantly diminished 3

Special Considerations for Pregnancy

Pregnancy does not preclude the use of optimal PEP regimens and should never be a reason to deny PEP. 1 The older 2001 guidelines specifically noted that zidovudine (ZDV) + lamivudine (3TC) was "probably a safe regimen for pregnant HCP," 4 but modern regimens are preferred due to better tolerability and single-tablet formulation.

Important caveats for pregnant women:

• Avoid efavirenz during pregnancy due to teratogenicity concerns 4
• Avoid indinavir during late pregnancy due to hyperbilirubinemia 4
• Expert consultation is advised for pregnant patients, but do not delay initiation while awaiting consultation 1

Baseline Assessment

Before or immediately after initiating PEP, perform: 1, 2

• Rapid or laboratory-based HIV antigen/antibody combination test 1, 2
• HIV nucleic acid test (NAT) if the patient received long-acting injectable PrEP in the past 12 months 1, 2
• Baseline renal function (creatinine, estimated GFR) 2, 3
• Pregnancy test for women of childbearing potential
• Assessment of concurrent medications for potential drug interactions 1, 2

Follow-Up Testing Schedule

• Within 72 hours: Clinical evaluation and assessment for drug toxicity 1, 2
• At 2 weeks: Monitor for drug toxicity 2
• At 4-6 weeks: HIV antigen/antibody test PLUS HIV nucleic acid test (NAT) 1, 2
• At 12 weeks (final): Laboratory-based HIV antigen/antibody combination immunoassay AND HIV nucleic acid test (NAT) 1, 2

Duration and Adherence

Complete the full 28-day course regardless of subsequent information about the source patient. 1, 2 The single-tablet BIC/FTC/TAF regimen achieves completion rates of 86-92%, significantly higher than older multi-tablet regimens (39-57%). 5, 6, 7

If the source is confirmed HIV-negative during the 28-day course, PEP can be stopped. 2, 3

Common Pitfalls to Avoid

• Never prescribe only two NRTIs (like tenofovir/emtricitabine alone) for PEP—this provides inadequate protection and requires a third drug (integrase inhibitor) 2
• Never delay initiation beyond 72 hours waiting for test results or consultations 1, 2
• Never use efavirenz in pregnant women or women who may become pregnant 4
• Never discontinue PEP prematurely based on side effects without switching to an alternative regimen 3

Counseling Requirements

Advise the exposed woman to: 1, 2

• Use precautions to prevent secondary transmission during the follow-up period (barrier methods during sex) 1, 2
• Seek immediate medical evaluation for any acute illness during follow-up, as this may indicate acute retroviral syndrome 1, 2
• Report side effects promptly rather than discontinuing medication 1

Transition to PrEP

For women with anticipated repeat or ongoing HIV exposures, consider immediate transition from PEP to PrEP after completing the 28-day course. 1, 2 Perform HIV testing at completion of PEP before transitioning to PrEP. 1, 2

Expected Side Effects

With modern regimens (BIC/FTC/TAF), more than 60% of patients report at least one adverse event, but these are typically mild to moderate: 5

• Most common: Fatigue, central neurological symptoms, abdominal discomfort, nausea 5, 7
• Serious toxicity is rare with modern regimens 1
• Side effects are manageable and rarely require discontinuation (only 3-4% discontinuation rate) 5, 8