Can I use MariaDB instead of MySQL in wordpress?

Is it possible to use MariaDB instead of MySQL in WordPress installation?
If possible: how do I do that?
Is there any drawback or complexities?

To answer your exact questions:

• Yes.
• Just use MariaDB instead of MySQL.
• No, it is a straight replacement.

The exact details depend heavily upon your exact situation. However, MariaDB is marketed as a compatible MySQL replacement. AFAIK, it works with WordPress with no changes at all.