I was prescribed Mirtazapine for sleep, but got achy legs??

Yes, I did. From what I read it is an uncommon side effect but listed nevertheless.
Certainly hope this is only a short term side effect which will resolve soon.
All the best.

It didn't resolve even when I started cutting the pills in half...only taking 3.25mg....pain persisted, so I quit taking it. And now my legs are fine. I' wasn't gonna let a medication (mirtazapine) ruin my legs!

O my goodness, leg pain even at 3.25 mg.!
I was on this medication @ 30 mg. for (believe it or not) 21 years and never had leg pain.
But I did see leg pain as an uncommon side effect. And you were one of the unlucky ones.
This medication, at the time, was a life saver for me. But after the length of time on it gradually became less effective in controlling my panic disorder. Really not a surprise.
It just re-enforces to me how medications can affect everyone so differently and we must take others experiences, with the same medication(s), with a grain of salt.
Consider yourself fortunate that you were able to pinpoint the culprit of your leg pain. Sometimes this is not such an easy thing to do...
Great news your legs are fine now!

I was given this drug last spring to help me gain weight. It also helps with anxiety and sleep. I saw the Dr every 2wks for a weight check. No gain. I would ask her if I could come off of it because I thought it wasn’t working. I thought she had given it to me to help me fall asleep and get some sleep. I told her it would take 4hrs after taking it before I was tired enough to fall asleep. She told me to just give it some more time and I agreed. Well after 4 months my appetite picked up and I started eating more and was able to gain a couple of pounds every 2 weeks.
I had and still have jumpy legs at night that I attribute to the medication. I take a CBD gummy within half an hour the jumping has stopped and/or I’ve fallen asleep. By morning I’m fine.

cindisue, you had several good suggestions for your leg pains. I just discontinued mirtazapine (SNRI) after starting it in 2001 (believe it or not). At that time it was a life saver for me. My anxiety was so severe as a result of PTSD.
I never had any side effects except for a major weight gain (not a good thing in the long run) but at the time I was unable to eat due to anxiety/panic. And could not sleep...obviously this medication was exactly what I needed. And I suppose I simply continued with it - as my severe panic disorder, to this day, remains with me.
However, after 22 years it was no longer effective and gradually came off of it to start a new SSRI.
I never had any leg issues...and I remember at the time discussing side effects with my psychiatrist who never brought up possible leg pains as a s/e and never did during my entire follow up with him.
But that's not to say mirtazapine is not the culprit with your leg pain.
I would simply say continue to monitor it but if no improvement perhaps further testing is needed to rule out multiple potential causes - & there are many. Good luck.

briarrose, yes my leg pain has gotten much better after several weeks of being off mirtazapine. Do you mind me asking which SSRI you started?

First, I went with Paxil, which was great for my PTSD, but found that my emotions felt very "blunted" and more disturbing was losing my appetite completely. Never feeling the sense of hunger anymore. I still ate, of course, but it was never enjoyable. I found this side effect to be very annoying but stuck it out for 8 weeks with it. I then decided this feeling of losing the feeling of hunger was enough to stop this medication and my provider agreed. It made me realized how awful this feeling must be to those suffering with cancer or another serious illness - losing your appetite...I never realized how terrible it can be. Right now I am 8 weeks or so on Zoloft. My appetite now normal but at 25 mg. I feel it's not working well enough to control my terrible anxiety/PTSD. In 2 weeks scheduled to increase it to 37.5 mg. (I am very sensitive to all medications now). But a possible odd side effect - which is uncommon, but can occur, although my provider says "no"...I have a constant pressure in my ears starting 4 weeks after starting this drug. Beyond painful at times. Seeing ENT and taking it from there...so my question to anyone on Zoloft & reading my post is - did you/or have ear problems since starting this drug?