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Gastrointestinal Medications Overview

Common GI drug classes for the PTCE Medications domain.

March 29, 2026

Why GI Medications Are Important

Gastrointestinal medications are among the most commonly dispensed drug categories. From acid reducers to anti-nausea drugs, these medications appear frequently on the PTCE and in daily pharmacy practice.

Proton Pump Inhibitors

Omeprazole (Prilosec) and pantoprazole (Protonix) reduce stomach acid production. They are taken before meals and are available in both prescription and OTC formulations. The "-prazole" suffix identifies this class.

H2 Receptor Antagonists

Famotidine (Pepcid) is the most commonly used H2 blocker, available OTC and by prescription. H2 blockers reduce acid production by a different mechanism than PPIs and are sometimes used in combination with them.

Antacids

Calcium carbonate (Tums) and aluminum/magnesium hydroxide (Maalox) provide quick, temporary relief of heartburn and indigestion. They work by neutralizing existing stomach acid rather than reducing its production.

Anti-Nausea Medications

Ondansetron (Zofran) is widely used for nausea and vomiting. Promethazine (Phenergan) is another option, though it has more sedating effects. Metoclopramide (Reglan) is used for certain GI motility issues and nausea.

Laxatives

Polyethylene glycol (MiraLAX) is a commonly used osmotic laxative available OTC. Docusate (Colace) is a stool softener frequently recommended for patients on medications that cause constipation, such as opioids.

Anti-Diarrheal Agents

Loperamide (Imodium) is the most common OTC anti-diarrheal. It slows intestinal motility and is available without a prescription.

Study Strategy

Organize GI medications by their function (acid reduction, anti-nausea, motility) rather than trying to memorize them as a single list. Knowing the function helps you answer questions even if you encounter an unfamiliar medication name, because you can use context clues from the question to identify the likely class.

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