Difference Between Bismuth Subsalicylate and Bismuth Subcitrate

Main Difference – Bismuth Subsalicylate vs Bismuth Subcitrate

Bismuth Subsalicylate and Bismuth Subcitrate are two forms of drugs used to treat diseases related to stomach or gastrointestinal tract. Bismuth Subsalicylate is a colloidal substance formed by the hydrolysis of bismuth salicylate. Bismuth Subcitrate is a bismuth salt of citrate ion. The main difference between Bismuth Subsalicylate and Bismuth Subcitrate is that Bismuth Subsalicylate is used as a medication to treat temporary discomforts in the stomach and gastrointestinal tract whereas Bismuth Subcitrate, along with metronidazole and tetracycline, is used to treat stomach ulcers.

Key Areas Covered

1. What is Bismuth Subsalicylate
     – Definition, Chemical Properties, Usage as a Drug
2. What is Bismuth Subcitrate
     – Definition, Chemical Properties, Usage as a Drug
3. What is the Difference Between Bismuth Subsalicylate and Bismuth Subcitrate
     – Comparison of Key Differences

Key Terms: Antacid, Bismuth, Bismuth Subcitrate, Bismuth Subsalicylate, Citrate Ion, Gastrointestinal Tract, Pepto-Bismol, Pink Bismuth, Salicylic Acid

What is Bismuth Subsalicylate

Bismuth Subsalicylate is a colloidal substance having the chemical formula C₇H₅BiO₄. It is an antacid used as a  medication to treat temporary discomforts in the stomach and gastrointestinal tract. The molar mass of this compound is 362.09 g/mol.

Figure 1: Chemical Structure of Bismuth Subsalicylate

Bismuth subsalicylate is a colloidal substance obtained by hydrolysis of bismuth salicylate. Therefore, bismuth subsalicylate is a derivative of salicylic acid. It is sold by its commercial name Pepto-Bismol and is also known as pink bismuth.

This drug is used to treat disorders such as diarrhea, indigestion, heartburn, and nausea. Since it is a derivative of salicylic acid, it also has anti-inflammatory and antacid actions. However, this drug has some adverse effects when used. It causes darkening of the tongue and results in black stool. But this darkening is temporary. Long term usage can cause accumulation and toxicity.

Unlike bismuth Subcitrate, some mechanisms of action of bismuth subsalicylate are known. For example, it is known to act through mechanisms such as binding with toxins produced by bacteria (ex: Escherichia coli), reduction in hypermotility of the stomach, etc.

What is Bismuth Subcitrate

Bismuth Subcitrate is a bismuth salt of citrate ion. Citrate ion is the conjugate base of the citric acid. There are two citrate ions in association with one bismuth cation and usually with three potassium cations as well. The chemical formula of bismuth Subcitrate is C₁₂H₁₄BiK₃O₁₄⁺⁴ and the molar mass is 708.505 g/mol. The IUPAC name of this compound is bismuth;tripotassium;3-carboxy-3,5-dihydroxy-5-oxopentanoate.

Bismuth Subcitrate is a soluble, complex compound used to treat stomach ulcers along with metronidazole and tetracycline. This drug is specifically used to treat stomach ulcers caused by the Helicobacter pylori infections.

Bismuth Subcitrate is very effective for gastrointestinal disorders. It acts against the disease via several mechanisms which are not clearly known. However, it has no considerable effect on neutralization of acid secretions. A well-known side effect of this drug is the darkening of the tongue, which is harmless and reversible. The absorption of bismuth Subcitrate is increased by omeprazole.

Difference Between Bismuth Subsalicylate and Bismuth Subcitrate

Definition

Bismuth Subsalicylate: Bismuth Subsalicylate is a colloidal substance having the chemical formula C₇H₅BiO₄.

Bismuth Subcitrate: Bismuth Subcitrate is a bismuth salt of citrate ion.

Molar Mass

Bismuth Subsalicylate: The molar mass of Bismuth Subsalicylate is 362.09 g/mol.

Bismuth Subcitrate: The molar mass of Bismuth Subcitrate is 708.505 g/mol.

Nature of the Compound

Bismuth Subsalicylate: Bismuth Subsalicylate is a colloidal substance.

Bismuth Subcitrate: Bismuth Subcitrate is bismuth salt of citrate ion.

Uses as Medication

Bismuth Subsalicylate: Bismuth Subsalicylate used as a medication to treat temporary discomforts in the stomach and gastrointestinal tract.

Bismuth Subcitrate: Bismuth Subcitrate is used to treat stomach ulcers along with metronidazole and tetracycline.

Conclusion

Bismuth Subsalicylate and Bismuth Subcitrate are drugs used to treat gastrointestinal diseases. The main difference between Bismuth Subsalicylate and Bismuth Subcitrate is that Bismuth Subsalicylate is used as a medication to treat temporary discomforts in the stomach and gastrointestinal tract whereas Bismuth Subcitrate, along with metronidazole and tetracycline, is used to treat stomach ulcers.

Reference:

1. “Bismuth subcitrate.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.
2. “Bismuth subcitrate.” Wikipedia, Wikimedia Foundation, 23 Jan. 2018, Available here.

Image Courtesy:

1. “Bismuth subsalicylate” By Edgar181 – Own work (Public Domain) via Commons Wikimedia