Bismuth subsalicylate

Bismuth Subsalicylate
Systematic (IUPAC) name
2-hydroxy-2H,4H-benzo[d]1,3-dioxa-2-bismacyclohexan-4-one
Clinical data
Trade names Pepto-bismol
MedlinePlus a607040
Pregnancy cat.  ?
Legal status  ?
Routes Oral
Identifiers
CAS number 14882-18-9 Y
ATC code None
PubChem CID 16682734
DrugBank DB01294
ChemSpider 17215772 Y
UNII 62TEY51RR1 Y
KEGG D00728 N
ChEBI CHEBI:261649 Y
ChEMBL CHEMBL1120 Y
Chemical data
Formula C7H5BiO4 
Mol. mass 362.093 g/mol
SMILES eMolecules & PubChem
 N(what is this?)  (verify)

Bismuth subsalicylate, with a nominal chemical formula of C7H5BiO4,[1] It is a colloidal substance obtained by hydrolysis of bismuth salicylate (Bi{C6H3(OH)CO2}3). The actual structure is unknown and the formulation is only approximate. Recent evidence indicates that it is composed of a bismuth oxide core structure with salicylate ions attached to the surface. A model structure has recently been published having the composition Bi38O44{C6H3(OH)CO2}26. It is a drug used to treat temporary discomforts of the stomach and gastrointestinal tract, such as diarrhea, heartburn and nausea. Commonly known as pink bismuth, it is the active ingredient in popular medications such as Pepto-Bismol and, since 2003, in Kaopectate.

Contents

Pharmacology

As a derivative of salicylic acid, bismuth salicylate displays anti-inflammatory action and also acts as an antacid.

Mechanism of action

Bismuth subsalicylate is used as an antidiarrheal and to treat some other gastro-intestinal diseases (oligodynamic effect).
The means by which this appears to work is still not well documented. It is thought to be some combination of:

Adverse effects and contraindications

There are some adverse effects. It can cause a black tongue and black stools in some users of the drug, when it combines with trace amounts of sulfur in saliva and the gastrointestinal tract to form bismuth sulfide.[2] This discoloration is temporary and harmless.

Some of the risks of salicylism can apply to the use of bismuth subsalicylate.[3][4][5]

Children should not take medication with bismuth subsalicylate while recovering from influenza or chicken pox, as epidemiologic evidence points to an association between the use of salicylate-containing medications during certain viral infections and the onset of Reye's syndrome.[6] For the same reason, it is typically recommended that nursing mothers not use medication containing bismuth subsalicylate (such as Pepto-Bismol) because small amounts of the medication are excreted in breast milk and pose a theoretical risk of Reye's syndrome to nursing children.[7]

Decomposition

Bismuth subsalicylate is the only active ingredient in an over the counter medication that will leave a shiny metal oxide slag behind after being completely burnt with a blow torch.[8]

References

  1. ^ Merck Index, 11th Edition, 1299
  2. ^ I noticed that Pepto-Bismol sometimes darkens the tongue/stool...
  3. ^ Drug information page at the National Institutes of Health
  4. ^ Sainsbury SJ (December 1991). "Fatal salicylate toxicity from bismuth subsalicylate". The Western journal of medicine 155 (6): 637–9. PMC 1003120. PMID 1812638. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1003120. 
  5. ^ Vernace MA, Bellucci AG, Wilkes BM (September 1994). "Chronic salicylate toxicity due to consumption of over-the-counter bismuth subsalicylate". The American journal of medicine 97 (3): 308–9. doi:10.1016/0002-9343(94)90017-5. PMID 8092182. http://linkinghub.elsevier.com/retrieve/pii/0002-9343(94)90017-5. 
  6. ^ Aspirin or Salicylate-Containing Medications, reyessyndrome.org
  7. ^ CDC warning about breastfeeding while taking bismuth subsalicylate compounds
  8. ^ Wesołowski, M. (1982). "Thermal decomposition of pharmaceutical preparations containing inorganic components". Microchimica Acta (Wien) 77 (5–6): 451–464. doi:10.1007/BF01197125.