About 8 days ago, I switched from mirtazapine to prozac, as I was feeling tired all the time. I'd been on 30mg of mirtazapine for a couple of months and the doctor said to do a straight swap. Is this the best way?

For the past 4 days I've been feeling sick constantly, I haven't been able to eat properly and unfortunately lost weight again. I've also been feeling a lot more anxious, dredging up old thoughts, and I had a weird anxiety thing (I wouldn't call it an attack exactly) 2 days ago, ringing my friend in a bit of a state.

I don't know if this is withdrawal from mirtazapine, start-up side-effects of prozac, or the mirtazapine was helping me more than I thought.

I can't see my doc for a week now, so I don't know what I should do. Should I stick with the prozac? Could I take the 15mg mirtazapine I still have in addition to help my appetite?

Anxiety and nausea are common start-up effects of SSRIs, including Prozac. They could also be discontinuation effects of going cold-turkey. Better known with SSRIs, but possible with a tetracyclic like mirtazapine. The safest way to stop taking any antidepressant is to reduce the dosage gradually.

Popping a mirtazapine probably would improve your appetite but who knows? You could make the rollercoaster ride even worse. I hope you can at least phone your doctor for some advice.

You are switching from a tetracyclic antidepressant to a SSRI one. Feeling sick and loss of appetite is often a side effect of Prozac and you may get withdrawals as your blood level of mirtazapine drops.

Go and see your Doctor for advise as self medicating is the worst thing you can do. As the last poster said at least phone your Doctor for advice.

Jim Bow

Thanks both.

I stayed off the mirtazapine. I continued to feel sick and after about 4 days it turned into a stomach bug, which my family had. I also stayed off the prozac for week, and on starting again I've felt sick again. So it could be one or all of three different causes. The anxiety was probably a mixture of things, feeling weak and ill not helping me.

It's lucky I didn't go back to the mirtazapine. I've read in the "dangerous side-effects" notes that I shold look out for signs of facial swelling, rashes, signs of infection like mouth ulcers. I did have a nasty little spot that made my cheek swell up while I was still on the mirtazapine. The swelling went down in a day or so, but I've these recurring cold-sore type spots by my nose which are sore and just a bit unsightly. If it comes back, it's another thing to pester my doctor about!

Taking no meds for that week did show me what a good job mirtazapine was doing for my mood - I feel slightly more awake but far more gloomy without the stuff.

This post has been edited by ReggiePerrin: Apr 21 2009, 09:48 AM

Some AD's can cause nausea. I recently tried Efexor which is fairly popular but after 3 days had to give it up because I could not cope with the severe nausea. I made two attempts with the same result. I find the mouth ulcers interesting. When I first started on paroxetine I had mouth ulcers for a year but when I mentioned it to my doc she did not think it connected. It was only later that there were warnings about it being a concern, but no explanation of why. After the first year the ulcers went away, at this stage I had no side effects apart from sexual and it worked well for around 10 years before it actually turned on me and produced the most awful anxiety type brain pain. Interestingly the sexual side effects also worsened. I have not experienced any of these problems with mitz. Mitz apparently blocks two synapse concerned with sex and anxiety. The scariest symptoms has been tinnitus, short term memory and confusion, the latter two being symptoms the same as for overdose. Fortunately these things have settled, I don't feel fantastic but at least I'm not suffering the terrible A & D that I have for the past year.

Warning --Doctors mine included seem to think that if you go from one AD to another that you will not get withdrawal symptoms. This is bull!!! be cautious because some people don't get withdrawal or they are mild but if you do then you will still get them if you swap suddenly. Also you will not know what is withdrawal of the old and what is side effects of the new. My experience was that to do a change I needed to ramp the old down and simultaneously ramp up the new. Be alert for Serotonin syndrome although I did not encounter any problems. My paroxetine withdrawal regime was 50% reduction every 5 to 6 weeks down to 5mg. At this point I experienced no problems with stopping even though my Doc seemed to think I would be stuck on small doses. I was on 20mg and went 20mg to 10mg to 5mg to 0 . between 10 and 5 seemed to be the critical jump presumably because the dose is too small to have an effect.

Thanks - I'll try and get my doctor to taper me off if I have to switch again. I had a look at serotonin syndrome, but apart from the sickness (which has passed and hasn't returned 4 days into taking prozac again) I haven't had those symptoms.

I'm glad to be through the worst of the withdrawals and I feel way more human in the past 2 days. Hopefully this is the firs signs of the prozac being good for me.

This post has been edited by ReggiePerrin: Apr 23 2009, 12:50 PM