All small business loans are either fixed-rate or adjustable-rate mortgages, i.e., either the monthly payment is fixed for the life of the loan or adjusts based on the underlying benchmark (commonly, Prime or 1-month LIBOR).
Fixed-rate mortgage: the interest rate and the monthly principal and interest (P&I) payments remain the same for the life of the loan
Adjustable-rate mortgage: the interest rate associated with the loan changes periodically and thus, the monthly principal and interest (P&I) payments change. For example, if the Prime rate changes (recently from 5.25% to 5.0%) the adjustable rate associated with the loan will fall by 0.25%.