What are alternative HIV regimens for a patient with an allergy to Truvada (emtricitabine/tenofovir disoproxil fumarate)?

Alternative HIV Regimens for Truvada Allergy

For patients with a documented allergy to Truvada, switch immediately to Descovy (emtricitabine/tenofovir alafenamide) combined with an integrase inhibitor such as bictegravir or dolutegravir as the preferred alternative regimen. 1

Preferred Alternative Regimens

Single-Tablet Complete Regimens

• Bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) is the most convenient option, providing a complete three-drug regimen in one tablet taken once daily 1, 2, 3
• This regimen demonstrated non-inferior efficacy to dolutegravir-based therapy through 96 weeks in treatment-naïve adults, with no resistance emerging to any component 3
• Dolutegravir plus emtricitabine/tenofovir alafenamide (DTG + FTC/TAF) is equally effective and recommended by current guidelines 4, 1

Key Advantages of Tenofovir Alafenamide Over Tenofovir Disoproxil Fumarate

• Superior bone mineral density preservation compared to the tenofovir formulation in Truvada 5, 6
• Improved renal safety biomarkers with significantly less nephrotoxicity 5, 6
• Non-inferior HIV prevention efficacy (0.16 vs 0.34 infections per 100 person-years) 5
• Can be used in patients with creatinine clearance ≥30 mL/min, whereas TDF requires ≥50 mL/min 3

Alternative Backbone Options (If Tenofovir Cannot Be Used)

If the allergy involves both tenofovir formulations or tenofovir specifically:

• Dolutegravir plus lamivudine (DTG + 3TC) is a viable two-drug regimen for treatment 1
• Abacavir/lamivudine (ABC/3TC) can replace the tenofovir backbone when combined with an integrase inhibitor 4
  • Critical caveat: HLA-B*5701 testing is mandatory before prescribing abacavir; those testing positive must never receive abacavir due to life-threatening hypersensitivity risk 4
  • Document any abacavir allergy prominently in the medical record 4

Special Considerations for HIV/HBV Co-infection

For patients co-infected with hepatitis B virus, maintaining anti-HBV activity is essential:

• Descovy (FTC/TAF) remains the preferred backbone as both emtricitabine and tenofovir have activity against HBV 1, 7
• If tenofovir cannot be used at all, consider entecavir as part of the HIV regimen for HBV management 1
• Never use lamivudine alone as the only anti-HBV agent due to high resistance rates (up to 70% at 5 years) 7
• Lamivudine monotherapy for HBV in HIV patients has led to transmission of resistant HBV strains in up to 10% of new infections 7

Dosing and Administration

• BIC/FTC/TAF: One tablet (50/200/25 mg) once daily with or without food 1, 2
• Descovy: One tablet (200/25 mg emtricitabine/tenofovir alafenamide) once daily 1
• Dolutegravir: 50 mg once daily when combined with FTC/TAF 8

Monitoring After Switching

• Perform HIV testing before initiating the alternative regimen 1, 2
• Follow-up HIV testing at 4-6 weeks and 12 weeks after exposure if used for post-exposure prophylaxis 1, 2
• Monitor for new adverse reactions specific to the alternative medication 1
• Assess renal function and bone density at baseline and periodically, especially in high-risk patients 5, 6

Critical Clinical Pitfalls to Avoid

Never prescribe emtricitabine/tenofovir (either formulation) alone without a third agent—this provides inadequate HIV protection and will lead to treatment failure. 9

• Do not discontinue HIV prevention or treatment without immediately replacing it with an alternative regimen 1
• Check for drug interactions, particularly with medications containing polyvalent cations (calcium, iron, magnesium) which can interfere with integrase inhibitor absorption 2
• For pregnant patients, dolutegravir with TAF/FTC is the recommended regimen 2
• Weight gain is more common with TAF-based regimens (median 1.7 kg vs 0.5 kg with TDF at 96 weeks), which should be discussed with patients 6