Epanutin capsules, oral suspension contain the active ingredient phenytoin, which is a type of medicine called an anticonvulsant.
Phenytoin prevents seizures by preventing the excessive electrical activity in the brain. It is thought to achieve this by preventing sodium from entering nerve cells when they begin to fire rapid and repetitive electrical signals. A build up of sodium in the nerve cells is necessary for the electrical signal to build up and be passed on to other nerve cells. As phenytoin prevents this, it helps stabilise the electrical activity in the brain.