Guidelines for Switching HIV Antiretroviral Therapy
Before switching any HIV regimen, you must comprehensively review the patient's complete ART history, prior resistance testing results, medication tolerability, drug-drug interactions, cost considerations, and HBV co-infection status 1, 2.
Pre-Switch Evaluation Algorithm
Perform this systematic assessment before any switch:
- Treatment history review: Document all prior regimens, duration of use, and reasons for discontinuation
- Resistance testing: Review all available genotypic resistance tests (current and historical)
- Adherence assessment: Evaluate current adherence patterns and barriers
- Drug interactions: Screen all medications, supplements, and over-the-counter products
- HBV status: Confirm HBV serology—this is critical and non-negotiable
- Comorbidities: Assess kidney function, cardiovascular risk, bone health, psychiatric conditions
- Cost and access: Verify insurance coverage and patient ability to obtain medications
Check viral load 1 month after any switch to confirm continued suppression 2.
Switching in Virologically Suppressed Patients
When to Consider Switching
Switch therapy in suppressed patients for these specific indications:
- Adverse effects or toxicity concerns
- Drug-drug interactions with new medications
- Regimen simplification to improve adherence
- Progressive kidney disease (switch from TDF)
- Cardiovascular risk factors (switch from boosted PIs)
- Cost reduction
- Patient preference for convenience
Preferred Switch Strategies for Suppressed Patients
For patients on boosted PI-based regimens with no prior NRTI resistance, switch to dolutegravir or bictegravir plus tenofovir/emtricitabine regardless of historical NRTI resistance 1. This is highly effective and supported by strong evidence.
Two-drug regimens are appropriate alternatives when both agents are fully active 2:
- Dolutegravir/lamivudine (evidence rating: AIa)
- Dolutegravir/rilpivirine (evidence rating: AIa)
- Boosted PI + lamivudine (evidence rating: AIa)
- Long-acting cabotegravir/rilpivirine every 4 weeks (evidence rating: AIa) or every 8 weeks (evidence rating: BIb)
Critical Restrictions for Suppressed Patients
Never switch from a boosted PI to an NNRTI or raltegravir if the patient has documented NRTI resistance mutations—this carries high risk of virologic failure 2.
Never use monotherapy with boosted PIs or dolutegravir—this is explicitly not recommended 2.
Special Population: HBV Co-infection
Patients with HBV co-infection MUST continue tenofovir alafenamide or tenofovir disoproxil fumarate 2. If you switch to a regimen without tenofovir (e.g., dolutegravir/lamivudine), you must add separate HBV-suppressive therapy. Lamivudine or emtricitabine alone without tenofovir will not maintain HBV suppression and risks HBV flare.
Switching for Virologic Failure
Immediate Actions
Obtain resistance testing while the patient is still taking the failing regimen, or within 4 weeks of stopping ART 2. Confirm virologic failure (HIV RNA >200 copies/mL) with a repeat test before making changes.
Evaluate adherence thoroughly—poor adherence is the most common cause of virologic failure, especially with high-barrier regimens like boosted PIs or dolutegravir 1.
Treatment Selection Based on Failing Regimen
After NNRTI failure:
- Switch to dolutegravir + 2 NRTIs (with ≥1 active NRTI based on resistance testing) 2
After integrase inhibitor failure:
- Switch to boosted PI + 2 NRTIs (with ≥1 active NRTI) 2
After raltegravir or elvitegravir failure:
- Use dolutegravir dosed twice daily plus at least 1 fully active agent 2
After boosted PI failure:
- Virologic failure with resistance is rare with PIs 2
- Focus on adherence support or switch to a regimen that improves tolerability/adherence
- If true resistance exists, construct new regimen based on resistance testing
Multiclass Resistance (3-Class Failure)
For extensive multiclass resistance including integrase inhibitors, use novel mechanism agents: ibalizumab, fostemsavir, or lenacapavir, ideally with 2 fully active drugs 1. These are the only options when traditional classes have failed.
Critical Rules for Virologic Failure
Never add a single active agent to a failing regimen—this promotes further resistance 2.
Never resume a previously failed regimen without resistance testing, unless it was a dolutegravir or bictegravir-based regimen with good adherence 1.
Special Circumstances
Patients Unable to Take Oral ART
For patients with advanced HIV disease (CD4 <200/μL) who cannot maintain oral adherence despite extensive support, consider long-acting cabotegravir/rilpivirine with intensive case management if the virus is susceptible to both drugs 1. This requires:
- Documented inability to take oral ART consistently
- High risk of disease progression
- Confirmed susceptibility to both agents
- Concurrent treatment of substance use disorders or mental illness if applicable
Resuming ART After Interruption
Resume the most recent dolutegravir or bictegravir-based regimen immediately, even before resistance test results return, provided adherence was good and the patient is willing 1. Do not delay restarting effective therapy.
Common Pitfalls to Avoid
Switching to low-barrier regimens in patients with archived resistance: Historical NRTI resistance persists even when not detected on current testing. Avoid NNRTIs or first-generation integrase inhibitors in these patients.
Forgetting HBV status: Always verify HBV serology before discontinuing tenofovir. HBV flares can be severe and life-threatening.
Inadequate monitoring post-switch: Increased clinical vigilance in the first 1-3 months catches pharmacy errors, dosing confusion, and unexpected toxicities.
Switching during active opportunistic infections: Ensure clinical stability before making regimen changes unless the switch is medically necessary.
Ignoring drug-drug interactions: Review tenofovir alafenamide dosing requirements with new medications, as boosting agents affect TAF levels 2.