Minoxidil is causing an excess of unwanted body hair

Unfortunately, if you stop using minoxidil you will begin to lose your hair regrowth everywhere. I suggest seeing a hair loss expert to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like PRP/progesterone that work well with hair transplantation. See an expert. Best, Dr. Emer

There's no good way to prevent this. Some people are sensitive to minoxidil which means that they can get great results on the scalp with the trade off being hair growth on the body at time. Once can consider removing the excess hair with laser, electrolysis, waxing and other mean. Reducing the amount of minoxidil is of course also a possibility - but will invariable lead to hair shedding on the scalp and hair loss on the scalp. You'll want to speak to a physician about a comprehensive plan that allows you to achieve your goals.

Minoxidil is a mild hair growth agonist which works generally on all hair types on the body which is why you are seeing hair growth in areas other than just on your head.  You will get better results by using a hair growth stimulant which is very specific and targets just the hair on your head (combined with an effective program to stop hair loss of course).

I recommend finding a hair regrowth specialist who can review your personal situation and create a perosnalized hair regrowth program which will target regrowing only the hairs on your head.