Almost all macro lenses can be used as a normal lens - the exception is the canon mpe-65.
The macro function is just its ability to focus very closely (i.e. subject is very close to the lens). Also macro lenses tend to have much finer focusing systems (both AF and manual) , these do tend to be slower than normal lenses.
For example I have a tamron 90f2.8Di, an excelent 90mm potrait lens, but focuses down to about 6-8cm or something, and like most macro lenses does '1:1" , where a 1mm long subject is projected onto the sensor at a length of 1mm.