Trimethobenzamide

Trimethobenzamide is an antiemetic used on patients with mild nausea that could lead to vomiting, such as gastroenteritis and medicine induced nausea. As it doesn't affect most of the major neurotransmitters, it has fewer side effects than other antiemetics. It works by suppressing a single receptor in the medulla oblongata. 
It can induce drowsiness, and can induce headaches and diarrhea.
Trimethobenzamide at Wikipedia