What is the typical timeframe to evaluate the effectiveness of a preventive therapy?

What is the typical timeframe to evaluate the effectiveness of a preventive therapy?

• A. About 2–3 months; adjust regimen if insufficient response
• B. Within 24 hours
• C. 6 weeks
• D. 12 months

Answer: (A)

Preventive headache therapies work by gradually altering brain pathways, so they need time to show their full effect on attack frequency and severity. The typical trial duration to judge effectiveness is about 2–3 months at a therapeutic dose; if there isn’t a meaningful reduction in migraine days or burden by then, the regimen should be adjusted or switched. Waiting only 24 hours belongs to acute treatment, not prevention. Six weeks may capture some early changes but usually isn’t enough to determine full benefit, and waiting a full year would delay optimization and patient improvement.

Preventive headache therapies work by gradually altering brain pathways, so they need time to show their full effect on attack frequency and severity. The typical trial duration to judge effectiveness is about 2–3 months at a therapeutic dose; if there isn’t a meaningful reduction in migraine days or burden by then, the regimen should be adjusted or switched. Waiting only 24 hours belongs to acute treatment, not prevention. Six weeks may capture some early changes but usually isn’t enough to determine full benefit, and waiting a full year would delay optimization and patient improvement.