Which NNRTI is associated with CNS adverse effects such as vivid dreams?

• A. Abacavir
• B. Efavirenz
• C. Lamivudine
• D. Tenofovir

Answer: (B)

CNS adverse effects are a known issue with some NNRTIs, and efavirenz is the one most classically linked to neuropsychiatric symptoms like vivid dreams, dizziness, and insomnia. This happens because efavirenz crosses the blood-brain barrier and affects CNS function, especially early in therapy. Many patients experience these dreams within the first few weeks, and they often improve with time; if the symptoms are bothersome, clinicians may adjust the dose timing (take at night) or consider switching therapy. The other drugs listed are nucleoside reverse transcriptase inhibitors, which have different toxicity profiles—for example, abacavir is notable for potential hypersensitivity reactions, while lamivudine and tenofovir mainly have effects on marrow, renal function, or bone density rather than CNS side effects like vivid dreams.