Why is Ebrantil (Urapidil) not FDA approved?

Ebtrantil (Urapidil) is commonly used as an antihypertensive in Europe, also due to its additive interaction with other antihypertensives, and less likely to alter the heart rate compared to similar alternatives .

However, the English Wikipedia article points out that it is not FDA approved in the U.S. What are the FDA’s concerns?