Firstly, there are more than 3 monotheistic religions. Secondly, Judaism and Christianity don't forbid interest-based loans.
From wikipedia:
> The Hebrew Bible regulates interest taking. Interest can be
> charged to strangers but not between those who are close to
> each other.
>
> Deuteronomy 23:20 Unto a foreigner thou mayest lend upon interest; but
> unto thy brother thou shalt not lend upon interest; that the LORD thy God
> may bless thee in all that thou puttest thy hand unto, in the land whither
> thou goest in to possess it.
As far as Christianity goes... the New Testament doesn't say anything about charging interest on loans. Attitudes have gone back and forth over the centuries.
The Koran, however, does completely forbid charging interest.