GI Pharmacology-1 (1) Flashcards
What are common disorders of the GI tract?
- Acidity
- Nausea
- Diarrhea
- Constipation
- Irritation
- Inflammation
What are the types of acid-related disorders?
- Ulcer
- Gastro-esophageal reflux disease (GERD)
What occurs in GERD?
Acid from the stomach refluxes into the esophagus, causing heartburn and potential serious damage.
What is the problem associated with GERD?
Both mechanical and related to acid production.
What receptors are involved in acid secretion?
- CCK2
- M3
- H2
- EP3
What does EP3 receptor bind to?
Prostaglandin E2 (PGE2).
What stimulates the H+, K+ ATPase?
- Acetylcholine (ACh)
- Gastrin
- Histamine
Agents that decrease acid secretion
Histamine-2 receptor (H2) antagonists
Proton pump inhibitors
Mucosal defense
Prostaglandins and coating agents
What is the mechanism of action of buffering agents?
Neutralizes H+ ions.
What are common prototypes of buffering agents?
- Ca2+ Carbonate
- Mg2+
- Al3+ hydroxide
What are the side effects of buffering agents?
Summary: simple to use, but not strong enough for many people
- Diarrhea (Mg2+)
- Constipation (Ca2+, Al3+)
What are agents that decrease acid secretion?
- Histamine-2 receptor (H2) antagonists
- Proton pump inhibitors
What is a prototype of Histamine-2 receptor (H2) receptor antagonists?
Ranitidine.
Side effects of Histamine 2 receptor
Generally well-tolerated - Ranitidine and famotidine are available without a prescription
What are potential side effects of cimetidine?
- Gynecomastia (an increase in the amount of breast gland tissue in boys or men
- Galactorrhea (milk production from the breast unrelated to pregnancy or lactation
What is the prototype of proton pump inhibitors?
Omeprazole.
What is the main action of proton pump inhibitors?
Irreversible inhibition of the proton pump.
What pharmacokinetic consideration is important for proton pump inhibitors?
Proton pumps must be active for inhibitors to bind and act.
What are some issues associated with long-term use of proton pump inhibitors?
- Reduced absorption of nutrients
- Alteration in GI flora
- Increased gastrin secretion (hypergastrinemia)
What are the potential risks associated with increased pH from proton pump inhibitors?
- Increased fracture risk
- Increased risk of infections, particularly GI infections like Clostridium difficile
What is the prototype for mucosal defense agents?
Misoprostol.
What are the side effects of Misoprostol?
- Diarrhea
- Abdominal cramping
- Contraindicated in pregnancy
What is the prototype for coating agents?
Sucralfate.
