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HIV — SCE Infectious Diseases MCQ

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ModerateHIV MedicineHIVSCE Infectious Diseases

A 38-year-old man is diagnosed with HIV with genotypic resistance testing showing K103N mutation. His CD4 is 350 cells/µL and viral load is 78,000 copies/mL. He has no other comorbidities. Which class of antiretroviral drug is rendered ineffective by this mutation?

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Correct answer: B — Non-nucleoside reverse transcriptase inhibitors (NNRTIs) – specifically Efavirenz and Nevirapine

K103N is the most common NNRTI resistance mutation. It confers high-level resistance to first-generation NNRTIs (Efavirenz and Nevirapine) but does not affect Etravirine or Rilpivirine (though other mutations may). This patient should be started on an INSTI-based regimen (e.g. DTG or BIC) with an NRTI backbone, avoiding NNRTIs. This highlights the importance of baseline genotypic resistance testing before initiating ART.

Reference: BHIVA 2025 – Guidelines on antiretroviral treatment for adults living with HIV-1 (2025 interim update)