What are the evidence-based approaches to migraine prevention?

Prevention indicated for ≥4 headache days/month or significant disability. First-line oral options: propranolol, metoprolol, topiramate, valproate, amitriptyline. CGRP monoclonal antibodies (erenumab, fremanezumab, galcanezumab) for patients failing or intolerant of traditional preventives. OnabotulinumtoxinA for chronic migraine. Lifestyle modifications: regular sleep, stress management, trigger avoidance. Allow 2-3 months for efficacy assessment before switching.