Which statement correctly describes the brexpiprazole 5-HT2A occupancy titration schedule?

• A. Days 1-4: 1 mg/day; Days 5-7: 2 mg/day; Day 8: 4 mg/day if needed.
• B. Days 1-2: 0.5 mg/day; Day 3-7: 1 mg/day; Day 8: 2 mg/day
• C. Days 1-4: 2 mg/day; Days 5-7: 4 mg/day; Day 8: 8 mg/day
• D. A fixed dose of 2 mg/day from day 1

Answer: (A)

The idea being tested is how to raise brexpiprazole to an effective level while keeping tolerability good by allowing gradual increases in 5-HT2A receptor occupancy. Brexpiprazole works best when receptor occupancy builds up slowly, so the body can adapt and you minimize adverse effects like akathisia or sedation.

This schedule starts at a low dose and steps up in small, time-separated increments, aiming toward the typical therapeutic dose. Beginning with 1 mg daily for several days gives a gentle initial occupancy, then moving to 2 mg daily for a few days increases occupancy further while still being tolerable. If needed, escalating to 4 mg daily on day eight reaches the higher end of the approved daily dose, allowing clinicians to balance efficacy with safety. Going straight to a 2 mg daily dose from the start or skipping the gradual increases can lead to too rapid a rise in occupancy and more adverse effects, and jumping to 8 mg would exceed recommended dosing. A fixed dose from day one eliminates the gradual buildup that helps patients tolerate the medication while achieving adequate receptor engagement.