A 28-year-old woman from Mumbai with HIV-1 infection (CD4 180 cells/µL, VL 95,000 copies/mL) is started on a first-line regimen: tenofovir disoproxil fumarate (TDF) + lamivudine (3TC) + efavirenz (EFV). After 3 months of adherent therapy, her CD4 count is 320 cells/µL and viral load is <50 copies/mL. However, she reports persistent dizziness, insomnia, and difficulty concentrating. She is considering stopping the medication due to intolerable side effects. Which of the following is the most appropriate next step?

Explanation

## Efavirenz (EFV) Neurotoxicity and Regimen Optimization ### EFV Neurotoxic Profile **Key Point:** Efavirenz is a potent NNRTI with excellent virologic efficacy but is associated with dose-dependent CNS side effects (dizziness, insomnia, impaired concentration, hallucinations, depression) in 40–50% of patients. These effects often persist beyond 4 weeks and significantly impact quality of life. ### CNS Side Effects of EFV - **Incidence:** 40–50% of patients experience CNS symptoms - **Onset:** Within days to weeks of initiation - **Severity:** Mild to severe; can be dose-dependent - **Timeline:** Symptoms may persist or worsen despite continued use (unlike early-onset side effects that resolve) - **Risk factors:** Psychiatric history, low body weight, high plasma concentrations ### Management Strategy for Intolerable EFV Toxicity **High-Yield:** When EFV causes intolerable CNS side effects in a patient with virologic success, the standard approach is **substitution with an alternative INSTI or PI**, NOT dose reduction or continuation with symptomatic management. | Option | Rationale | Outcome | |--------|-----------|----------| | **Switch to INSTI (dolutegravir)** | Maintains backbone; excellent efficacy; minimal CNS toxicity; once-daily dosing | Recommended first-line substitution | | **Switch to PI** | Effective but more GI side effects; higher pill burden; requires boosting | Acceptable alternative if INSTI contraindicated | | **Continue EFV + symptom management** | Symptoms often persist; poor adherence risk; suboptimal QoL | NOT recommended | | **Dose reduction** | EFV is fixed-dose formulation; reduction compromises efficacy; not standard practice | NOT appropriate | ### Why Dolutegravir (DTG) is Optimal Here 1. **Efficacy:** Integrase inhibitors (INSTIs) are superior to NNRTIs in virologic potency 2. **Safety:** Minimal CNS toxicity; well-tolerated neuropsychiatric profile 3. **Backbone preservation:** TDF + 3TC remains effective; no need for complete regimen overhaul 4. **Adherence:** Once-daily dosing improves compliance 5. **Guideline-aligned:** WHO and Indian guidelines recommend INSTI-based regimens as preferred first-line for treatment-naïve patients **Clinical Pearl:** Switching from EFV to DTG in a virologically suppressed patient typically results in rapid resolution of CNS symptoms (within 1–2 weeks) and improved quality of life without loss of virologic control. **Mnemonic — EFV Toxicity Management (SWITCH):** - **S**witch agent (do not continue) - **W**hy? Intolerable CNS effects - **I**NSTIs are first choice (dolutegravir, bictegravir) - **T**DF + 3TC backbone maintained - **C**ontinue monitoring VL and CD4 - **H**ealth-related QoL improves [cite:Harrison 21e Ch 197; WHO Guidelines 2023]