PrEP Recommendation for Injection Drug User with High HIV Risk
Emtricitabine/tenofovir disoproxil fumarate 200/300 mg orally daily is the best PrEP regimen to recommend for this patient with injection drug use who shares needles. 1
Rationale for Recommendation
Patient Risk Assessment
- 35-year-old cisgender man with:
- Active injection drug use with needle sharing
- History of skin abscesses from "skin popping"
- Heterosexual relationship (monogamous per patient report)
Evidence-Based Recommendation
Daily TDF/emtricitabine (Truvada) is specifically recommended for people who inject drugs with an evidence rating of BIa 1. This patient's needle-sharing behavior places him at substantial risk for HIV acquisition, making him an ideal candidate for PrEP.
The International Antiviral Society-USA Panel guidelines clearly state that:
- PrEP is recommended for populations with an HIV incidence above 2% per year 1
- For people who inject drugs, TDF/emtricitabine is recommended over TDF alone 1
- Daily dosing is required for optimal protection 1, 2
Why This Option Over Alternatives
Why TDF/FTC over TAF/FTC
While emtricitabine/tenofovir alafenamide (TAF/FTC) has shown non-inferior efficacy to TDF/FTC for sexual exposure in MSM and transgender women 3, it has not been adequately studied or approved for PrEP in people who inject drugs 2. The guidelines specifically state that "TDF/lamivudine, TAF/emtricitabine, or TDF alone are not recommended for PrEP" 1, 2.
Why Not Cabotegravir
Although cabotegravir long-acting injectable is FDA-approved for PrEP 4, it has not been specifically studied in people who inject drugs. The current evidence and guidelines strongly support TDF/FTC as the first-line recommendation for this population 1, 2.
Why PrEP Is Indicated
This patient clearly meets criteria for PrEP based on:
- Active injection drug use with needle sharing (high-risk behavior)
- History of skin abscesses indicating unsafe injection practices
- Guidelines specifically recommend PrEP for people who inject drugs 1, 2
Implementation Considerations
Baseline Testing
Before initiating PrEP:
- HIV testing (combination antigen-antibody assay)
- Serum creatinine and estimated GFR
- Hepatitis B surface antigen
- STI screening
- Substance use assessment 1, 2
Monitoring
- HIV testing every 2-3 months
- Renal function monitoring every 3-6 months
- STI screening every 6 months 2
Adherence Support
Daily adherence is crucial for PrEP efficacy, especially in people who inject drugs 5. The patient should be counseled that:
- Daily dosing is required for optimal protection
- PrEP does not protect against other infections
- Continued needle sharing remains high-risk behavior
Comprehensive Harm Reduction
PrEP should be part of a comprehensive approach:
- Clean injection equipment and access to substance use treatment 1
- Opioid substitution therapy if appropriate 1
- Regular STI screening
- Condom provision for sexual risk reduction
- Support for the patient's journey toward sobriety
Potential Pitfalls and Caveats
- TDF-based PrEP is contraindicated if creatinine clearance is below 60 mL/min/1.73m² 1, 2
- Monitor for potential renal adverse events, which occur at a higher rate with TDF/FTC compared to placebo (RR 1.43) 5
- Gastrointestinal side effects may occur but are usually mild and reversible 5
- PrEP effectiveness decreases significantly with suboptimal adherence 5
By providing emtricitabine/tenofovir disoproxil fumarate 200/300 mg daily along with comprehensive harm reduction services, this patient can significantly reduce his risk of HIV acquisition while working toward sobriety.