I have no idea, because you gave me no amount
If the medicine killed all the bacteria, you wouldn't be able to sustain other bad bacteria, for your body holds the amount of bacteria that is needed to live. Your vitamin production decrease, and you probably wouldn't be able to survive for long. One of your needs to survive for your body is to be able to have bacteria to fight off viruses, to protect your body from the outside, some bacteria is needed to give nutrients or signals to the brain.
Look it up in google it will help a lot better