In the mean time there are probably plenty of other forums on here that have discussed this!
In theory, there are no AS requirements for medicine. However, the standard offer for medicine courses is AAA (+), so you'd need some compelling evidence that you could achieve that.
That said though - are you confident you can get AAA now? Or that your school will predict you it with Cs at AS? If you are eligible you could also look at getting a lower offer due to widening access criteria.