A patient with HIV develops immune reconstitution inflammatory syndrome (IRIS) after starting antiretroviral therapy (ART). The regimen includes efavirenz. Efavirenz's characteristic CNS side effects (vivid dreams, dizziness) are primarily due to its action on:
- A Inhibition of central dopamine D2 receptors
- B Potentiation of GABA-A receptors and inhibition of serotonin 5-HT2A and 5-HT3 receptors in the CNS ✓
- C Inhibition of central cholinergic muscarinic M1 receptors
- D Blockade of N-methyl-D-aspartate (NMDA) glutamate receptors in the limbic system
Correct answer: B. Potentiation of GABA-A receptors and inhibition of serotonin 5-HT2A and 5-HT3 receptors in the CNS
Explanation
Efavirenz, a non-nucleoside reverse transcriptase inhibitor (NNRTI), has off-target CNS effects attributed to its modulatory activity at GABA-A receptors (potentiation) and serotonin receptors (5-HT2A and 5-HT3 antagonism/inverse agonism). These interactions manifest as vivid dreams, nightmares, dizziness, impaired concentration, and occasionally psychosis (especially in patients with psychiatric comorbidities). CNS symptoms often improve after 2–4 weeks; taking efavirenz at bedtime and avoiding high-fat meals reduces peak levels and symptom intensity.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.