If you're asking whether you can deduct medical expenses that you've paid out of a loan you've taken out, the answer is yes. You can claim the expenses in the tax year you paid them, not when you actually make the loan payments.
However, you must itemize deductions to get a tax benefit.
See the TurboTax article Standard Deduction vs. Itemized Deductions: Which Is Better? for information on itemizing. Also, see the TurboTax Help article Can I deduct medical expenses? for guidance on entering medical expenses.