Definitely make sure you have cleared up the UTI before taking steroids. The point of steroids is to damp down your immune system, so that the inflammation which is causing the relapse symptoms is reduced. The problem with taking steroids if you have an infection though is that your immune system can’t fight the infection.
Steroids are supposed to shorten the relapse, but they don’t ‘cure’ it. This is the reason why many people refuse to take them. The side effects are sometime, for some people, just not worth the potential benefits.
If you have cleared up the UTI and you are going ahead with the steroids, my preference would always be for IV rather than oral. I think they work better, plus, it’s 3 days rather than 5, so the side effects are over a bit sooner. But I’ve not often had a choice.
The side effects for both are similar. Sleeplessness, edginess, a vile taste in your mouth, post steroids a bruised feeling (like I’ve been kicked by a horse in all my muscles). Some people are actually psychotic because of them. (A good reason for many people to avoid them!)
You can also never predict whether they will work or not. Each time can be different. They might work once, but next time not.
I’ve taken them lots of times, sometimes against my own better judgement, a kind of ‘well if I don’t, I might regret it’, type of thing (much like taking DMDs to be honest). Sometimes they’ve seemed to work and other times, they’ve made no difference.