 Several drugs that act as 5-HT4 selective agonists have recently been introduced into use in both scientific research and clinical medicine.Some drugs that act as 5-HT4 agonists are also active as 5-HT3 antagonists, such as mosapride, metoclopramide, renzapride, and zacopride, and so these compounds cannot be considered highly selective.Research in this area is ongoing.