Menopause is not a contraindication to fasting.
The "change" as it often referred to as, is due to the normal cessation of certain functions of the ovaries and to changes in these.
Hot-flashes and other nervous symptoms, high or low blood pressure, mental symptoms, etc., commonly blamed on the change are of toxic origin: the toxemia resulting from enervation growing out of youthful imprudence's, and wrong food choices and other lifestyle habits, etc.
You will need to correct all devitalizing habits post fast, and build good health thereafter which will remove the symptoms of ill-health. The "change" per se is not pathological and nothing can be done for it, but healthful lifestyle habits post fast will improve your health enormously.
I'm 57, postmenopausal, and never had any problems during the transition. I am a habitual faster though.
Listen to your body. It will tell you what it needs.
My body tells me that it wants to fast again. I am completing my first water-only fast day today and hope to last at least 10 more days. Will be happy if my body lets me do it at least for 21 days. 21 is my magic number - Black Jack of fasting.
I had an argument with a guy in my health club sauna. The dork asked how old I was and I told him "forever 21." He told me that I looked like I was forty - his wife was forty and according to his opinion, I looked the same age as his wife, maybe a little bit fitter. I didn't know how to react to that, I was making a joke. Anyway, I decided that it's time for my seasonal rejuvenation.
But I never tell anyone how old I am - it helps to fool my body that it's forever 21. That's why I try to be anonymous here, so my body will not know the truth. ;-)