First decide if you really need to amend, since:
1) You don't get the benefit of medical expenses if you are taking the standard deduction.
2) If you itemize deductions, you will only be able to take total medical expenses that are greater than:
- 10% of your adjusted gross income if you are under age 65; or
- 7.5% of your adjusted gross income if you are age 65 or over (born before January 2, 1951).
If you do decide to amend, see below:
https://ttlc.intuit.com/replies/3288565