I'm so glad that you posted because I can relate/help you with everything you brought up!
I also have the spasms in my feet and they are brutal, let me tell you! Sometimes, I can't sleep at night because of them- I'm constantly trying to maneuver my feet to such an angle so as to stop them, but they just end up twisting back inwards in contortions that are really painful. I don't have them everyday, so again, it must be something I'm eating or not eating...I think it's potassium, or lack of it. I'm low on it. During my last plasma exchanges, they checked it out, and it was low every time since I've started taking the prednisone (got a full synopsis of my history). So I guess we gotta increase our potassium intake- I hear cantaloupes are full of it, and bananas of course (but then you gotta be aware of the sugar content, so that's another one-argh).
The salt thing is definately bad. The worst thing about it is that I started to crave salt like crazy since starting the prednisone, whereas before, I didn't feel like eating it so much-weird! One time, I devoured an entire bag of Hostess potato chips, and Lord, I payed. I felt almost instant pressure in my face, and I got dizzy. I think that it increased my BP big time. Who knew an innocent bag of deliciousness with such friendly-looking mascots on the bag could be like a grenade! lol..Suffice it to say, no more chips. It's still very difficult to control the salt, though, even when preparing your own meals from scratch. I find breakfast easy (scrambled, unsalted eggs, whole grain toast, tomatoes, milk and a banana and maybe cereal- no salt added to anything), but dinner is hard because I love meat, and it's got so much salt.
I completely empathize with your feelings of sadness/frustration. The prednisone doesn't even control my symptoms enough for it to be really worth it (in light of the LT side-effects of the treatment). I still have to have plasma exchanges every once in a while (which work spectacularly, much better than they did before, so I guess the prednisone helps a touch). So I feel like I've bargained for new diseases in order to take the edge off of the MG. Now I'm stuck with the scary side-effects because I can't just come off of it- I really hate that my body is dependant on this poison, but am thankful that it helps a teensy bit. My neuro. now wants me to start Imuran, and i'm putting it off (being a bad patient). I'm really scared to take combo. immunosuppressive therapy because there's a risk of cancer and life-threatening infections. Plus the side-effects of that one are pretty bad too. It's really hard to know what to do in this situation. I just think that it's dangerous to still be at a relatively high dose of prednisone and to start a high dose of another immunosuppresive agent simultaneously. It might be rare, but I've read that this combo. can cause PML, and it scares me a lot. *sigh*. I'm sitting on this dilemma, and trying to work through what I should do.
You asked about how long it takes to be weaned off the prednisone. My impression is that, for MG at least, when the side-effects get to be too much, and/or another agent is added, and/or improvement is seen, the weaning starts. I think that I remember you mentioning that your MG is sorta well-controlled now with the pred. and mestinon. Maybe you can start weaning now, or in the near future.
About work- I had to apply for LTD. The continuing speech/breathing issues along with the prednisone side-effects are just too much for me right now. I was approved, thank God. I've read about others taking prednisone for other illnesses and being approved for disability based on the side-effects of the prednisone alone. I mean think about it, we basically have Cushing's disease- this is a disability in of itself, you know? Every organ in the body is affected. It's difficult. I hope that I'm not being negative, or a 'downer,' it's just that it is what it is, at least for now. I have so much hope for the future, but right now I feel that I'm still transitioning- getting used to the new me, limitations. I hope that something works well soon.
About the side-effects while tapering- I seriously think that 50mgs is a magic number for me, at least in terms of the moon face. Again, it could also be the reduction in salt, but my face is actually normal right now, and let me tell you that it was gigantic before. I sorta don't feel as moody either, or 'foggy.' My cognitive abilities are still sorta lax, but I feel like they're improving somewhat. It's funny because my dad was at a very high dose for his illness too a while back. When he got down to 40mgs, his moonface completely disappeared, which is very odd 'cause 40mgs is still a high dose. Who knows!
Anyway, know that you're not alone, and thanks for writing. I hope that you can start weaning very soon and that the MG remains at bay!
Nicky