A client is recently diagnosed with HIV and a highly antiretroviral therapy is started. After the first week of therapy, the patient complains of headache, dizziness, and nightmares. Which one of the following anti-retroviral drugs is most likely associated with these symptoms?

Efavirenz is a non-nucleoside reverse transcriptase inhibitor. Side effects include rash, dizziness, confusion, headache, and nightmares. Options A and C: Lamivudine and Tenofovir side effects includes headache, dizziness, nausea, diarrhea, or trouble sleeping. Option D: Saquinavir can cause headache, nausea, diarrhea, and photosensitivity.