What is the recommended post-exposure prophylaxis (PEP) regimen for a patient with recent Human Immunodeficiency Virus (HIV) exposure, potentially with impaired renal function?

HIV Post-Exposure Prophylaxis (PEP)

Initiate bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) 50mg/200mg/25mg as a single tablet once daily for exactly 28 days, starting immediately—ideally within 1-2 hours but no later than 72 hours post-exposure. 1, 2

Immediate Action Protocol

Do not delay PEP initiation for any reason. Start treatment immediately upon presentation without waiting for: 2

• HIV test results from the exposed person
• Source patient testing or identification
• Risk stratification assessments
• Specialist consultation

Efficacy decreases dramatically with each passing hour, and the 72-hour window represents an absolute maximum beyond which PEP is not recommended. 2, 3

Preferred Medication Regimens

First-Line Regimen

BIC/FTC/TAF (bictegravir 50mg/emtricitabine 200mg/tenofovir alafenamide 25mg) as one tablet once daily for 28 days. 1, 2 This regimen offers:

• Superior renal and bone safety compared to older tenofovir formulations 1
• Improved completion rates due to single-tablet dosing 1
• Better tolerability profile 2

Alternative Regimen

Dolutegravir (DTG) 50mg once daily PLUS emtricitabine/tenofovir alafenamide (FTC/TAF) 200mg/25mg once daily for 28 days when BIC/FTC/TAF is unavailable or contraindicated. 1, 2

Renal Impairment Considerations

For patients with impaired renal function, use tenofovir alafenamide (TAF) instead of tenofovir disoproxil fumarate (TDF) due to improved renal and bone safety profiles. 1 If TAF is unavailable, TDF 300mg can be substituted, though TAF remains strongly preferred. 1

Baseline Assessment (After First Dose)

Perform these assessments after initiating the first dose, not before: 1, 2

• Rapid or laboratory-based HIV antigen/antibody combination test
• HIV nucleic acid test (NAT) if the patient received long-acting injectable PrEP in the past 12 months
• Baseline renal function (creatinine, estimated GFR)
• Hepatitis B surface antigen (HBsAg)
• Pregnancy test
• Testing for other sexually transmitted infections

Critical Duration Requirement

Complete the full 28-day course regardless of any subsequent information about the source patient. 1, 2 There is no option for early discontinuation, as incomplete adherence significantly reduces effectiveness. 1, 2

Provide anti-emetics or other supportive medications proactively to manage side effects like nausea and fatigue, and schedule follow-up visits or phone check-ins during the 28-day course to encourage adherence. 1

Follow-Up Testing Schedule

Within 72 hours after starting PEP:

Clinical evaluation and assessment for drug toxicity. 1

At 4-6 weeks post-exposure:

• Laboratory-based HIV antigen/antibody test PLUS HIV nucleic acid test (NAT) 1, 2

At 12 weeks post-exposure:

• Laboratory-based HIV antigen/antibody combination immunoassay AND HIV nucleic acid test (NAT) 1, 2

Immediate testing if:

Acute retroviral syndrome symptoms develop (fever, rash, lymphadenopathy, pharyngitis, myalgias), regardless of timeline. 1, 4

Exposures Warranting PEP

PEP is indicated for exposures to: 3

• Bodily fluids: Blood, blood-stained saliva, breast milk, genital secretions, semen, vaginal secretions, rectal secretions, cerebrospinal fluid, amniotic fluid, peritoneal fluid, synovial fluid, pericardial fluid, or pleural fluids
• Mucous membrane exposures: Sexual exposure, splashes to eye, nose, or oral cavity
• Parenteral exposures: Needlestick injuries, human bites with blood exposure

Exposures NOT Requiring PEP

Do not initiate PEP when: 3, 1

• The exposed individual is already HIV-positive
• The source is confirmed HIV-negative
• Exposure involves non-infectious fluids: tears, non-blood-stained saliva, urine, sweat, feces, vomitus, sputum, or nasal secretions

Counseling Requirements

Advise the exposed person to: 1, 2

• Use barrier precautions (condoms) to prevent secondary transmission during the follow-up period
• Seek immediate medical evaluation for any acute illness during follow-up
• Avoid breastfeeding during PEP and follow-up period
• Report any side effects promptly

Special Populations

Pregnancy

Pregnancy does not preclude the use of optimal PEP regimens and should not be a reason to deny PEP. 1 However, avoid efavirenz (EFV) due to teratogenic effects observed in primate studies, and avoid the combination of stavudine (d4T) and didanosine (ddI) due to reports of fatal lactic acidosis in pregnant women. 3 Expert consultation is advised for pregnant patients. 1

Children and Adolescents

The same principles apply, with therapy started as soon as possible after exposure—no later than 72 hours—and continued for 28 days. 5 Dosing should be adjusted based on weight and age, in consultation with a clinician experienced in treating HIV-infected children. 5

Transition to PrEP After Completing PEP

Consider immediate transition from PEP to PrEP for persons with anticipated repeat or ongoing HIV exposures. 1, 2 Perform HIV testing at completion of the 28-day PEP course before transitioning to PrEP. 1, 2

Common Pitfalls to Avoid

• Never delay PEP initiation for source testing, risk assessment, or specialist consultation 1, 2
• Never use two-drug regimens unless three-drug options are absolutely unavailable 1, 2
• Never discontinue PEP early based on subsequent source patient information 1, 2
• Never fail to assess for drug interactions with concurrent medications 1, 2
• Never prescribe older regimens (such as zidovudine-based regimens) when modern single-tablet options like BIC/FTC/TAF are available 1, 2