Can I take a gap year and study another course whilst doing medicine?

I would like to have a short break from medicine and study other subjects for a brief period of time (i.e. mathematics, physics or computing).

You can interrupt but need to have a good reason for doing so (usually health or extenuating circumstances related) but not to go off to do something else and I ca't imagine you'd get finance for that either.

Oh well that's a shame....
I was told by one of my relatives that it was possible, I can't remember of the name of this procedure...
Basically it had something to do with studying a course you're interested in whilst your primary course. We were talking about Oxbridge, however, so it might only apply to those.
Does this sound familiar to you? I am dying to remember what he called it....

They could be talking about intercalating but that is still part of and relevant to your degree and career. It is optional and isn't only available at Oxbridge.

Right, so can you give me a brief description on what I can or can't choose?
Isn't maths, physics or computing applicable with medicine?

Not quite. More like something life sciences related or medical education or medical physics, bioinformatics. Maybe do some of your own research as well. This is your future.