$50,000 at, say 8% interest, over 9 years (4 years of med school + 5 years of residency/fellowship), with $0 payments over that period against the interest/principal, will essentially double (~$102K) over that period. That will very likely be less than half of your attending post-tax income.
Putting even $200/month toward that balance once you enter residency drops that to $88,000. If you were to finish in 3 years instead of 5, knock another $10K off of that.
In summary, don't do this.