Omeprazole-induced increase in the absorption of bismuth from tripotassium dicitrato bismuthate

Treiber, Gerhard; Walker, S. A.; Klotz, Ulrich

doi:10.1038/clpt.1994.61

Cited by 33 publications

(22 citation statements)

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“…This difference could reflect a pH difference as ranitidine increases the intra‐gastric pH. This is consistent with other studies indicating that an increase in intragastric pH will increase the systemic bismuth accumulation if bismuth compounds are given together with omeprazole (Treiber et al 1994).…”

Section: Discussionsupporting

confidence: 90%

Gastrointestinal and Systemic Uptake of Bismuth in Mice after Oral Exposure

Martiny¹,

Stoltenberg²,

Danscher³

et al. 2003

Pharmacology & Toxicology

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The aim of this study was to screen the inhibitory potential of different clinically used oestrogen and progestin hormones on CYP2C9, 2C19 and 3A4 activities in human liver microsomes. The degree of inhibition by desogestrel, 3-ketodesogestrel, 17-beta-oestradiol, gestodene, aethinyloestradiol, medroxyprogesterone acetate, norethisterone or L-norgestrel were studied at 100 microM on losartan oxidation (CYP2C9), R-omeprazole 5'-hydroxylation (CYP2C19) and R-omeprazole sulphoxidation (CYP3A4) with a 10-min preincubation with NADPH in human liver microsomes prepared from 6 individual genotyped donor livers. Aethinyloestradiol was found to be a potent inhibitor (55% mean inhibition; 95% CI 32% to 79%) of losartan oxidation (CYP2C9) and R-omeprazole 5-hydroxylation (70%; 63% to 77%) (CYP2C19), while it had little effect on R-omeprazole sulphoxidation (CYP3A4) activity. 17-beta-Oestradiol did not produce significant inhibition on any of the studied enzyme activities. Of the progestin hormones studied, gestodene and 3-ketodesogestrel were potent inhibitors of CYP2C19 (57%; 47% to 67% and 51%; 29% to 45%) and CYP3A4 (45%; 30% to 59% and 40%; 19% to 62%), but had little effect on the CYP2C9 activity. In addition, medroxyprogesterone acetate was found to inhibit CYP2C9 (55%; 45% to 65%), while not having significant effect on 2C19 or 3A4. In conclusion, the liability of clinically used female sex steroids to inhibit CYP2C9, 2C19 and 3A4 activities in human liver microsomes is very distinctive and these differences among both the oestrogen and progestin hormones may, at least in part, explain the variable results from clinical trials examining inhibitory effects of hormone replacement therapy and oral contraceptives on drug metabolism.

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Section: Discussionsupporting

confidence: 90%

Gastrointestinal and Systemic Uptake of Bismuth in Mice after Oral Exposure

Martiny¹,

Stoltenberg²,

Danscher³

et al. 2003

Pharmacology & Toxicology

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“…22 Recently an increase in the absorption of bismuth from tripotassium dicitrato bismuthate after omeprazole has been described. 23 The correlation between gastric pH and the extent of methadone absorption and effects suggests that pharmacologically induced changes in gastric pH may play an important role in the observed variability in methadone levels and effects, and that these could be of clinical importance. However, one must not forget that other factors such as gastrointestinal motility, food, and metabolic capacity of the liver may also be involved.…”

Section: Discussionmentioning

confidence: 98%

THE EFFECT OF CHANGES IN GASTRIC pH INDUCED BY OMEPRAZOLE ON THE ABSORPTION AND RESPIRATORY DEPRESSION OF METHADONE

Castro

Aguirre

Rodríguez-Sasiaín

et al. 1996

Biopharm. Drug Dispos.

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The effect of omeprazole (2 mg kg−1 i.v.) on respiratory depression induced in rats by acute oral methadone administration (5 mg kg−1) was examined and compared with control animals that only received methadone. Quantitative assessments of arterial pCO2, pO2, pH, and respiratory rate were employed as criteria for evaluation. Intragastric pH was measured in each rat immediately before and 2 h after methadone. Plasma concentration of methadone was measured for 3 h. The relationship between drug effect and the systemic bioavailability of methadone, measured as the area under the plasma concentration–time curve (AUC0–180 ), was also evaluated. The intensity of the methadone‐induced respiratory depression was significantly greater in the omeprazole group than in control rats. A significant variation (p<0·01) in all respiratory parameters was detected from 30 to 120 min after methadone. Omeprazole caused a significant increase in methadone levels (Cmax=156± 6·5 ng mL−1 against 51±5·8 ng mL−1 in control; p<0·05). AUC0–180 was higher (p<0·05) after omeprazole treatment (18·6±1·4 μg mL−1 min) than in control (6·8± 0·6 μg mL−1 min). Two hours after treatment with omeprazole, intragastric pH values were significantly elevated (4·7±0·1 against 2·2±0·04) and continued increasing, being 6·4±0·1 at the end of the experiment. Correlation was observed between intragastric pH and the area under the effect– (respiratory depression–) time curve (r=0·74; p<0·001). A relationship between plasma methadone levels at 120 min and gastric pH (r=0·92; p<0·001) was detected. A significant correlation between the area under the effect–time curve (0–120 min) and AUC0–180 has been also observed (r=0·90; p<0·01). These pharmacokinetic and pharmacodynamic changes could be gastric pH dependent because they were mimicked when gastric pH was experimentally modified by bicarbonate whereas opposite results were obtained with acidic pH 2 solution.

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“…administration of bismuth salts and thiolates increases the bismuth level in blood plasma (Williams, 1977;Chaleil et al, 1981). Increased bismuth levels in blood have also been reported after an increase of intragastric pH by the application of ranitidine or omeprazole (Nwokolo et al, 1991;Treiber et al, 1994): the solubility of colloidal bismuth subcitrate ranges from less than 1 mg/ml at acidic pH to several hundred milligram per milliliter in pure water (Sun et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Determination of Trimethylbismuth in the Human Body after Ingestion of Colloidal Bismuth Subcitrate

Boertz¹,

Hartmann²,

Sułkowski³

et al. 2008

Drug Metab Dispos

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ABSTRACT:Biological methylation and hydride formation of metals and metalloids are ubiquitous environmental processes that can lead to the formation of chemical species with significantly increased mobility and toxicity. Whereas much is known about the interaction of metal(loid)s with microorganisms in environmental settings, little information has been gathered on respective processes inside the human body as yet. Here, we studied the biotransformation and excretion of bismuth after ingestion of colloidal bismuth subcitrate (215 mg of bismuth) to 20 male human volunteers. Bismuth absorption in the stomach and upper intestine was very low, as evidenced by the small quantity of bismuth eliminated via the renal route. Total bismuth concentrations in blood increased rapidly in the first hour after ingestion. Most of the ingested bismuth was excreted via feces during the study period. Trace levels of the metabolite trimethylbismuth [(CH 3 ) 3 Bi] were detected via low temperaturegas chromatography/inductively coupled plasma-mass spectrometry in blood samples and in exhaled air samples. Concentrations were in the range of up to 2.50 pg/ml (blood) and 0.8 to 458 ng/m 3 (exhaled air), with high interindividual variation being observed. Elimination routes of bismuth were exhaled air (up to 0.03‰), urine (0.03-1.2%), and feces. The site of (CH 3 ) 3 Bi production could not be identified in the present study, but the intestinal microflora seems to be involved in this biotransformation if accompanying ex vivo studies are taken into consideration.It is a well known fact that the toxicity of metal(loid)s is essentially dependent on the chemical form, i.e., on the species of the element in question (Craig, 2003;Dopp et al., 2004; Hirner and Emons, 2004). In particular, alkylation often seems to considerably increase the toxic potential of metal(loid)s. Many studies have shown that in the environment methylated and also, in some cases, hydride species can be formed by different mechanisms and from a variety of metal(loid)s (Craig, 2003). In particular, microorganisms, e.g., bacteria and fungi, have been reported to be involved in this specific kind of conversion (Thayer, 2002).In contrast to the considerable knowledge that has accumulated on the interaction of microorganisms with metal(loid)s in the environment, a paucity of information is currently available on the respective processes inside the human body. This lack of knowledge is particularly striking in view of the fact that certain segments of the digestive tract, namely, the oral cavity and the colon, are colonized by myriads of bacteria. The difficulty of analyzing metal(loid) organic compounds at trace and even ultratrace levels might at least partly account for this information gap.After a pilot study with three volunteers , we performed an ingestion experiment with bismuth, administering this element as a single p.o. dose to 20 male volunteers in the form of a therapeutically used colloidal bismuth subcitrate compound. Bismuth was chosen as the element of interest ...

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Omeprazole-induced increase in the absorption of bismuth from tripotassium dicitrato bismuthate

Cited by 33 publications

References 0 publications

Gastrointestinal and Systemic Uptake of Bismuth in Mice after Oral Exposure

Gastrointestinal and Systemic Uptake of Bismuth in Mice after Oral Exposure

THE EFFECT OF CHANGES IN GASTRIC pH INDUCED BY OMEPRAZOLE ON THE ABSORPTION AND RESPIRATORY DEPRESSION OF METHADONE

Determination of Trimethylbismuth in the Human Body after Ingestion of Colloidal Bismuth Subcitrate

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