Gastrointestinal Pharmacology – BCSE Study Guide

Overview and Clinical Importance

Gastrointestinal (GI) disorders are among the most common presentations in veterinary practice across all species. Understanding GI pharmacology is essential for the entry-level veterinarian because these drugs are used daily for managing vomiting, diarrhea, constipation, gastric ulcers, and motility disorders. The BCSE tests your ability to select appropriate drugs based on mechanism of action, species differences, and clinical indications.

This guide covers five major categories of GI drugs: Antiemetics, Antidiarrheals, Laxatives and Cathartics, Antacids/H2 Blockers/Proton Pump Inhibitors, and Prokinetics. Each section emphasizes mechanisms of action, clinical applications, species considerations, and common exam pitfalls.

Section 1: Antiemetics

Antiemetics are drugs that prevent or treat vomiting (emesis). Understanding the emetic pathway is crucial for selecting the appropriate antiemetic. The vomiting reflex involves multiple receptors in the chemoreceptor trigger zone (CRTZ), emetic center, vestibular apparatus, and peripheral GI tract.