Bismuth subcitrate

Bismuth subcitrate potassium is a bismuth salt used in combination with antibiotics and a proton pump inhibitor for the treatment of Helicobacter pylori infections.^[1][2]

Bismuth subcitrate

Clinical data
Routes of administration	Oral
ATC code	A02BX05 (WHO)
Identifiers
IUPAC name Bismuth(3+) potassium 2-olato-1,2,3-propanetricarboxylate (1:5:2)
CAS Number	880149-29-1
PubChem CID	124490479
DrugBank	DB09275
ChemSpider	32821371
UNII	BQE6KE1T4H
KEGG	D09739
ECHA InfoCard	100.055.320
Chemical and physical data
Formula	C12H8BiK5O14
Molar mass	780.654 g·mol−1
3D model (JSmol)	Interactive image
SMILES C(C(=O)[O-])C(CC(=O)[O-])(C(=O)[O-])[O-].C(C(=O)[O-])C(CC(=O)[O-])(C(=O)[O-])[O-].[K+].[K+].[K+].[K+].[K+].[Bi+3]

A fixed-dose combination with the antibiotics metronidazole and tetracycline is sold under the trade name Pylera.^[3]

Contraindications

Further information: Bismuth subcitrate/metronidazole/tetracycline § Contraindications

Side effects

Further information: Bismuth subcitrate/metronidazole/tetracycline § Adverse effects

A known side effect of bismuth salts is harmless and reversible darkening of tongue and stool by formation of bismuth sulfite.^[3] Other side effects of bismuth containing combination therapies are often difficult to assign to a specific component.^{[citation needed]}

Interactions

Bismuth absorption is increased by ranitidine and omeprazole.^[3]

Pharmacology

Mechanism of action

The mechanism of action of bismuth is not known. It has been reasoned to interfere with the function of the bacterial cell membrane, protein and cell wall synthesis, the enzyme urease, cell adhesion, ATP synthesis, and iron transport mechanisms.^[3]

Chemical properties

Bismuth subcitrate potassium is a salt of bismuth (Bi³⁺), potassium (K⁺) and citrate (C₆H₄O4−7) in a molar ratio of about 1:5:2, with 3 moles of water. It contains about 25.6% (mass percent) bismuth, which is the active moiety, and 22.9% potassium.^[3][4] Other sources give somewhat different ratios of the constituents.

See also

• Helicobacter pylori eradication protocols
• Bismuth subsalicylate