How long will migraines and other side effects last from stopping mirtazapine 15mg after being on 30mg for 11 months? i am still taking 150mg of venlifaxine, but gp wanted me to stop mirtazapine due to intolerable side effects and inability to sleep.

Depends : Recommend slow reductions over 1-2 weeks if been on < 2 months and perhaps even slower withdrawal over 6-8 weeks if you've been on it longer. You may wish to have further discussion with your gp in consultation with mental health re best way to switch

Weeks: People's experience can vary but the minimum would probably be 1-2 weeks and the maximum around 6-8 weeks.

It: Varies. You may need another medication for migraines depending on the frequency and intensity of your symptoms