I am not sure about type of tablets in US, but in India we get
coreg(local name is cardivas) delayed
release tablets. And if you split them they act much faster(not over a period) due to opening of its coating. In India we get them in tablets of 3.125mg, 6.25mg, 12.5mg and 25mg.I also take ACE-I(Ramipril) which dilates the arteries and also lowers BP. Coreg also effects BP but not much.