Enteric coated - It can increase the chance of a stomach ulcer, reducing the amount of the drug in the body if it is broken down by acid in the stomach or stopping the drug from getting to where it needs to work. For this reason, you should never crush enteric coated tablets.
Modified release, crushing it may cause the drug to all be released at once and therefore increase the chance of side effects and give you some time with no drug in the body at all. Again, modified release tablets should never be crushed.
Reference : http://www.swallowingdifficulties.com/