There is no need to worry about electrolyte levels on a 10 day fast, it's a rare problem on any fast and 10 days is not a long term fast for us. Taking salt during your fast could be dangerous and I would advise against it.
You will need medical advice about fasting on your medication. There are fasting supervisors who have the experience and understanding of the effect of taking medication during a fast.
You will find a list of fasting retreats around the world on this page: