Antibotics i dont know the full legal thing may be some of the others know for sure.
But from my limited knowledge prescription drugs imported in to the Uk with out the right paperwork a prescription from A doctor if discovered by a customs officer could leave you in a bit of dilemena.
http://www.britainusa.com/sections/a...23&a=28529&D=3
I would check for the latest regulations the bother you could get for bringing in a few pills could affect the rest of your life.
Also if you fly via another country do check the laws and regulations they have.
A woman was jailled for carrying a British prescription drug in UAE if i recall the news story corrctly.
Also do you need them? I know taking Antibiotics at the wrong time can affect your immune system long term. If you need them a doctor will prescribe them.