Een arts vraagt mij naar capsules met bismut, eventueel magistraal te bereiden. Deze zouden gebruikt worden in een combinatie-therapie voor de uitroeiing van Helicobacter Pylori.

Wanneer u onderstaande link consulteert, dan vind je het oorspronkelijk artikel, die deze combinatie-therapie bespreekt.
http://www.med.upenn.edu/gastro/documents/HpyloriQuadtherapylancet2011.pdf
Er wordt blijkbaar gebruik gemaakt van kalium bismutsubcitraat. Dit product, dat zich toch onderscheidt door een grotere oplosbaarheid in water, van bismutsubcarbonaat of-nitraat, is niet verkrijgbaar in België. Maar in het tijdschrift Helicobacter. 2000 Sep;5(3):176-82 lezen we:

Solubility, absorption, and anti-Helicobacter pylori activity of bismuth subnitrate and colloidal bismuth subcitrate: In vitro data Do not predict In vivo efficacy. Phillips RH, Whitehead MW, Lacey S, Champion M, Thompson RP, Powell JJ.

Gastrointestinal Laboratory, The Rayne Institute, St. Thomas' Hospital, London, UK.

Abstract

OBJECTIVES:
The aim of this study was to compare the dissolution, bioavailability, and anti-Helicobacter pylori activity of bismuthsubnitrate and colloidal bismuth subcitrate. This could, first, provide insights into the mechanism of action of bismuth and, second, help to develop optimal therapeutic strategies.

METHODS:
Solubility and aquated size of bismuth species were determined in human gastric juice, while absorption into blood and urinary excretion of bismuth was determined in volunteers. Activity against H. pylori was determined in vitro in the presence and absence of antibiotics, while H. pylori eradication was compared in vivo.

RESULTS:
Bismuth from colloidal bismuth subcitrate was at least 10% soluble and ultrafilterable and was absorbed in volunteers (>0.5%), whereas that from bismuth subnitrate was insoluble and not absorbed (<0.01%). Colloidal bismuth subcitrate was active against H. pylori (mean inhibitory concentration, 400 microg/ml); neither was synergistic with antibiotics. With in vivo triple therapy, bismuth subnitrate was as effective as colloidal bismuth subcitrate in eradicating H. pylori (74% and 70% eradicated, respectively).

CONCLUSIONS:
Colloidal bismuth subcitrate, unlike bismuth subnitrate, is partially soluble, absorbed in humans, and directly toxic to H. pylori in vitro. Surprisingly, however, these preparations had similar efficacy in vivo against H. pylori within triple therapy, suggesting that bismuth compounds may also exhibit indirect antimicrobial effects. We propose that this is an effect on the gastric mucus layer. Nonabsorbable bismuth compounds should be preferentially considered in bismuth-based therapies against H. pylori, as they would minimize toxicity while maintaining efficacy.

De capsules PYLERA^TM: (bismuth subcitrate potassium, metronidazole, and tetracycline hydrochloride) 140 mg/125 mg/125mg zouden als voorbeeld kunnen dienen met vervanging van het substraat door het subcarbonaat dat misschien nog te verkiezen is boven het nitraat.