Loan Repayment on 1099-MISC--how to report so not taxed?

Several years ago we made a $10,000 loan investment to a local business. This year they paid back $5,000 of the loan and $600 interest. They sent a 1099-MISC for $5600. Only $600 should be taxable. How do I handle this for the 1040 tax form so that I don't pay tax on the $5000 Loan?