Yes,
you can even deduct the cost of having the hot tub installed if it was prescribed, as you
stated, and it is for the treatment of a disease/health issue. Remember, it is important that you will be
the only one using the hot tub if you would like to deduct 100% of its
cost. If anyone else uses it, you can
only deduct a portion based on the percent of use by the other person/people.
See IRS publication
here to learn more and exactly how much of a deduction you will receive. An excerpt regarding
the hot tub is attached as a screen shot.