Jill's response is wrong. Coreg is a beta blocker, not an ACE inhibitor. In fact, it is a combination alpha and beta blocker.
The CR version is the longer acting med and it is dosed once a day. Coreg is not a combination pill as it does not contain a diuretic. For what it it worth, as I am on the drug myself, it is a newer generation beta blocker which has been shown to reduce mortality in congestive heart failure patients. So it is a proven drug with fewer side effects and better results than older beta blockers.