TDS on interest on loan paid

it is depend upon which  kind of assessee you are talking about.

If you are talking about other than banks & in the whole year interest that you have paid has crossed Rs.5000/-, then you are liable to deduct tds(for banks limit is Rs10,000/-) u/s 194A

Interest on loan paid is allowed as business expense, but if you are required to deduct tds & not deducted, then it will attract penalty provisions.

If interest on loan is paid to Non resident without deduction of TDS then that interest on loan is NOT allowed to be deducted as business expenditure