Active Component of Carafate (Sucralfate)
Sucralfate is a basic aluminum salt of sucrose octasulfate (sucrose octakis(hydrogen sulfate) aluminum complex) that forms an ulcer-adherent complex at duodenal ulcer sites, protecting the ulcer and promoting healing. 1
Chemical Structure and Composition
Sucralfate's chemical structure consists of:
- α-D-glucopyranoside
- β-D-fructofuranosyl
- Octakis(hydrogen sulfate)
- Aluminum complex
The molecular formula can be represented as [R = SO₃Al(OH)₂], where the aluminum component is essential to the medication's therapeutic action 1.
Mechanism of Action
Sucralfate works through a local rather than systemic action in the gastrointestinal tract. Its therapeutic effects occur through several mechanisms:
- Formation of protective barrier: It forms an ulcer-adherent complex with proteinaceous exudate at the ulcer site 1
- Acid protection: Creates a barrier that prevents diffusion of hydrogen ions 1
- Pepsin inhibition: Inhibits pepsin activity in gastric juice by approximately 32% 1
- Bile salt adsorption: Adsorbs bile salts that can damage the gastric mucosa 1
These combined actions result in a physical protective coating over ulcerated areas that shields them from further damage by acid, pepsin, and bile salts 2.
Pharmacokinetics
- Absorption: Minimally absorbed from the gastrointestinal tract (only about 3-5%) 3
- Distribution: Remains at the site of gastric ulcers for up to six hours 3, 4
- Excretion: The small amounts absorbed are primarily excreted in the urine, while more than 90% is excreted unchanged in the feces 1, 3
Clinical Applications
While primarily used for peptic ulcer disease, sucralfate has been utilized in various gastrointestinal conditions:
- Treatment of duodenal and gastric ulcers 2
- Prevention of NSAID-associated duodenal ulcers 2
- Management of gastroesophageal reflux 5
- Topical application for wound healing in epithelial injuries 6
Important Considerations
- Sucralfate has approximately 14-16 mEq of acid-neutralizing capacity per 1g dose 1
- It has greater affinity for ulcerated mucosa than normal mucosa, making it selective in its action 4
- Unlike H2-receptor antagonists or proton pump inhibitors, sucralfate does not significantly alter gastric pH 3
- It is well-tolerated with minimal side effects, with constipation being the most common (occurring in 2-4% of patients) 3, 7
Sucralfate's unique mechanism of forming a protective barrier at ulcer sites distinguishes it from other anti-ulcer medications that primarily work by reducing acid production, making it valuable in specific clinical scenarios where mucosal protection is the primary goal.