This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Anitibiotic that improves gastroparesis is: 
Select and explain. 
A. Ciprofloxacin, B. Erythromycin, C. Chloramphenicol, D. Vancomycin
B: Erythromycin
Answer: B: Erythromycin 
Explanation: Macrolide antibiotics such as erythromycin directly stimulate motilin receptors on gastrointestinal smooth muscle and promote the onset of a migrating motor complex. Intravenous erythromycin (3 mg/kg) is beneficial in some patients with gastroparesis; however, tolerance rapidly develops. It may be used in patients with acute upper gastrointestinal hemorrhage to promote gastric emptying of blood before endoscopy. Ref: Katzung 11th edition Chapter 60.