Yes ask your doc for a script of low dose Prozac and do a "prozac bridge."
Prozac has a really long half life compared to other ssris it's half life is about 7 days wheras mirtazapine
is only c. 30 hours. The shorter the half life means that when you come off , the last dose quickly depletes from your system and then the rapid lack of serotonin causes the withdrawal effects.
The benefit of switching to Prozac is that it's such a long half life means it takes over a month to leave your system from the last dose ,so transferring over from mirtazapine to Prozac
prevents a rapid drop in serotonin instead the Prozac will just wean itself off naturally over a month or so to depletion of serotonin.
This results in fewer withdrawal effects and a much smoother ride.
You have two options
1. If your withdrawal are too uncomfortable and you want them gone now! go back to the lowest dose of Mirtazapine that you were in without any withdrawls and continue again until you no longer have unbearable withdrawls, but ideally no longer than a week or 10 days
then stop Mirtazapine and start the Prozac Bridge the next day
2. if your withdrawals are manageable for a few more days. Then stop the Mirt and start the Prozac Bridge immediately.
The Prozac Bridge method :-
Take one dose of Prozac at 10 mg, one each day for the next two days; or if your symptoms are so bad take 20mg per day for the next two 2 days or 3 days if severe.
Then you get on with life and just wait for the Prozac to gradually go away over the next several weeks.
Since the small upfront stack of Prozac you built up in the bloodstream is much smaller than the levels one gets to after a month or more of normal 20 mg daily dosing, the prozac depletes quite
quickly to near 0 and just leaves a tiny amount in the blood so there is no sudden cliff edge drop in seretonin. Hopefully by then you will be
med free and also symptom free and you probably won't even have noticed.
So you should ask your doctor for say a weeks worth of 10mg Prozac which gives you enough for the 10mg,20mg, 2 or 3, day options
You might also ask for a few Diazepam or Lorazepam to help whilst you wait for the heeby jeebies to subside.