Determination of bismuth in blood and urine

Iatrogenic bismuth toxicity associated with inadvertent long term De-Noltab ingestion

A prolonged course of oral tripotassium dicitratobismuthate (De-Noltab) was administered to an elderly woman. The patient developed extrapyramidal neurological symptoms and subsequently sustained accidental fracture of the right neck of the femur before bismuth toxicity was identified. The parkinsonian features that presented in this patient were thought to be possibly related to the accumulation of bismuth in the basal ganglia as a result of the long term ingestion of tripotassium dicitratobismuthate.

Prolonged treatment with the drug should be discouraged and repeat prescriptions should always be queried.

Long-term efficacy of bismuth carbomer enemas in patients with treatment-resistant chronic pouchitis

BACKGROUND

Mucosal inflammation of the ileal pouch (pouchitis) is the major long-term complication after ileal pouch-anal anastomosis for ulcerative colitis. Broad-spectrum antibiotics are the mainstay of treatment, however, 15% of patients with pouchitis have a chronic, treatment-resistant disease.

AIM

To determine the safety and efficacy of bismuth carbomer enemas in achieving and maintaining remission in treatment-resistant chronic pouchitis.

METHODS

Twelve patients with treatment-resistant chronic pouchitis were treated nightly for 45 days with enemas containing elemental bismuth complexed with carbomer. Diagnosis of pouchitis and response to treatment were evaluated with the Pouchitis Disease Activity Index (PDAI), which includes clinical, sigmoidoscopic and histological criteria. Serum bismuth concentrations were determined by atomic absorption.

RESULTS

Ten of 12 patients (83%) went into remission, with a significant decrease of mean total PDAI score from 12 (range 9-15) to 6 (4-15) (P < 0.002), and were continued on bismuth carbomer enemas administered every third night for 12 months. Patients were monitored clinically, sigmoidoscopically and histologically every 2 months for evidence of recurrence (increase > or = 2 in the clinical symptom portion of the PDAI). Six of 10 patients (60%) were able to maintain remission throughout the 12-month trial; 4/10 had an exacerbation, two of which occurred soon after discontinuing daily treatment. Serum bismuth levels were negligible in all patients and no side-effects were registered.

CONCLUSIONS

Our findings suggest that bismuth carbomer enemas are safe and effective in achieving and maintaining remission in patients with treatment-resistant chronic pouchitis.

GR122311X (ranitidine bismuth citrate), a new drug for the treatment of duodenal ulcer

BACKGROUND

Ranitidine bismuth citrate (GR122311X) is a new drug which offers potential benefits in healing duodenal ulcers and prevention of relapse.

METHODS

This randomized, multi-centre double-blind study of 1620 patients compared the effect of 4 weeks of treatment with GR122311X 200 mg b.d. (n = 401), 400 mg b.d. (n = 404) or 800 mg b.d. (n = 404) or ranitidine hydrochloride 150 mg b.d. (n = 411) on the rates of duodenal ulcer healing and of overall success (ulcers healed and remaining ulcer free in the 24-week follow-up phase).

RESULTS

All four treatments were equally effective at ulcer healing (79%, 85%, 84% and 81% of patients, respectively). GR122311X 400 mg b.d. (38%) and 800 mg b.d. (37%) were significantly more effective than ranitidine hydrochloride 150 mg b.d. (32%) with respect to overall success (P = 0.050 and P = 0.030, respectively) but there was no difference with GR122311X 200 mg b.d. (31%). GR122311X caused effective, dose-related suppression of H. pylori (47%, 61% and 74%); H. pylori eradication rates were 18%, 21% and 22%. GR122311X was safe and well tolerated, with an adverse event profile similar to that of ranitidine hydrochloride 150 mg b.d. Median week 4 trough plasma bismuth levels were 1.3 ng/mL, 2.3 ng/mL and 3.3 ng/mL with GR122311X 200 mg b.d., 400 mg b.d. and 800 mg b.d. respectively. No individual plasma bismuth concentrations were of clinical concern.

CONCLUSIONS

GR122311X is a safe and effective ulcer healing drug, and provides a platform on which anti-H. pylori therapy can be based.

Lack of evidence of neurotoxicity following 8 weeks of treatment with tripotassium dicitrato bismuthate

OBJECTIVE

To search for evidence of subclinical neurotoxicity in patients treated with tripotassium dicitrato bismuthate.

DESIGN

Prospective, controlled, triplicate study using urinary bismuth concentration, magnetic resonance imaging (MRI), nerve conduction studies, visual evoked response and a battery of 10 neuropsychological screening tests.

SETTING

Out-patient clinics, Walsgrave Hospital, Coventry, UK.

SUBJECTS

Fourteen dyspeptic patients; 8 (treatment group) treated with tripotassium dicitrato bismuthate one tablet q.d.s and 6 (control group) treated with ranitidine 150 mg b.d. for 8 weeks.

MAIN OUTCOME MEASURES

Changes in urinary bismuth, MRI, nerve conduction studies, visual evoked response, and neuropsychological tests performed before, immediately after and 8 weeks after the cessation of treatment.

RESULTS

In the treatment group the median (range) urinary bismuth concentration was 1 (1-12) ng/ml before treatment, increased to 560 (140-1300) immediately after treatment (P < 0.01, Wilcoxon Rank Sum test) and was still significantly elevated (23 (7-53) ng/ml) 8 weeks after the cessation of treatment. In the patient who recorded the highest urinary bismuth, a high intensity signal appeared in the globus pallidus immediately after treatment and was still present (though diminished in intensity) 8 weeks after the cessation of treatment. This isolated MRI finding was not associated with evidence of subclinical neurotoxicity. No changes in the MRI, nerve conduction studies, visual evoked response and neuropsychological tests were observed among the other patients studied.

CONCLUSIONS

Bismuth accumulation occurs in patients receiving a conventional course of treatment with tripotassium dicitrato bismuthate but this is not associated with significant changes in the nervous system.

Comparison of bismuth citrate and 5-aminosalicylic acid enemas in distal ulcerative colitis: a controlled trial

An enema that contained a complex of bismuth citrate and polyacrylate was compared with 5-aminosalicylic acid (5-ASA) enemas for treatment of distal ulcerative colitis. The multicentre trial involving 63 patients was randomised and double blind with enemas given over four weeks; clinical, sigmoidoscopic, and histological assessments were made. Improvements were seen in both treatment groups. Clinical remission was seen in 18 of 32 patients treated with 5-ASA and 12 of 31 patients treated with bismuth citrate-carbomer (chi 2 1.94; p = 0.16). Sigmoidoscopic remission occurred in 20 of 32 patients in the 5-ASA group and 15 of 31 patients given bismuth (chi 2 1.27; p = 0.26). Improvement of rectal biopsy histology by at least one grade was seen in 16 of 32 patients in the 5-ASA group and 14 of 31 patients with bismuth (chi 2 0.15; p = 0.70). Analysis of covariance gave no significant difference between groups, although there was a trend favouring 5-ASA. There was no evidence of bismuth accumulation during the trial. Bismuth enemas may offer a new therapeutic option in distal ulcerative colitis.

Management and response to treatment of Helicobacter pylori gastritis

Gastritis associated with Helicobacter pylori was present in gastric biopsies from 24/95 (25%) children and adolescents undergoing endoscopy for recurrent abdominal pain and upper gastrointestinal symptoms. H pylori associated gastritis occurred mainly in older children (8-16 years) and was significantly associated with low socioeconomic class and a family history of peptic ulcer disease. Antral nodularity was a common endoscopic finding in H pylori positive children. Eighteen children, all over 5 years of age, were treated with tripotassium dicitratobismuthate (De-Nol) for two months and ampicillin for two weeks. In 12 children follow up gastric biopsies were obtained six weeks after completion of treatment. In 9/12 (75%) children H pylori was eradicated, and gastritis improved.

The effect of histamine H2-receptor blockade on bismuth absorption from three ulcer-healing compounds

Twelve healthy male subjects were dosed with six regimens: ranitidine and De-Noltab (tripotassium dicitrato bismuthate; Gist-Brocades Ltd., Weybridge, England), placebo and De-Noltab, ranitidine and Pepto-Bismol liquid [bismuth salicylate; Procter & Gamble (Health and Beauty Care) Ltd., Egham, England], placebo and Pepto-Bismol, ranitidine and Roter tablets (bismuth subnitrate; Roter Pharma Ltd., Ashford, England), and placebo and Roter. Ranitidine, 300 mg, or placebo was administered at 10 PM (night before) and at 7 AM; at 9 AM, the oral dose of bismuth was either 2 De-Noltabs, 3 30-mL doses of Pepto-Bismol liquid, or 2 Roter tablets. When predosed with placebo, the median integrated 8-hour plasma bismuth concentration was significantly greater after dosing with De-Noltabs than after dosing with either Pepto-Bismol or Roter (61, 8, and 8 ng.h/mL, respectively), with a similar trend for 8-hour median urinary bismuth excretion (213, 40, and 6 micrograms, respectively). When predosed with ranitidine, only after De-Noltab administration were there significant increases in the 8-hour plasma bismuth concentration (147 ng.h/mL), and 8-hour urinary bismuth excretion (686 micrograms). Eliminating intragastric acidity may enhance bismuth absorption after oral dosing with De-Noltabs by maintaining intragastric tripotassium dicitrato bismuthate as a colloidal suspension.

The effect of GR122311X, a bismuth compound with H2-antagonist activity, on 24-hour intragastric acidity

GR122311X (ranitidine bismuth citrate Glaxo Group Research Ltd) is a bismuth compound with histamine H2-receptor antagonist activity. The gastric acid antisecretory activity of three oral dosage regimens of GR122311X was compared with placebo and 150 mg ranitidine b.d. The median 24-h integrated intragastric acidity was 38, 26 and 18% of the median placebo value during dosing with GR122311X 196, 391 and 782 mg b.d., respectively. The 24-h acid suppression with GR122311X 391 mg b.d. was not significantly different to that produced by 150 mg ranitidine b.d. (24% of placebo acidity). The median 24-h urinary bismuth excretion increased with rising dosage of GR122311X from 19.2 micrograms with 196 mg b.d., to 36.4 micrograms with 391 mg b.d., to 68.7 micrograms with 782 mg b.d. In conclusion, GR122311X is an effective antisecretory agent with modest systemic bismuth absorption.

Analysis of bismuth in serum and blood by electrothermal atomic absorption spectrometry using platinum as matrix modifier

Bismuth-containing medicines have been used for years, but there is a lack of clinically applicable methods for measuring bismuth in body fluids. We describe a sensitive, accurate and precise method for analysis of bismuth in blood and serum, which is suitable both for monitoring purposes and for further investigations into the biokinetics and safety of bismuth. Bismuth was quantitated with electrothermal atomic absorption spectrometry with Zeeman background correction. In the furnace programme a cool-down step was introduced and platinum was used as a matrix modifier. Recovery for 40 micrograms/l is 93.7 +/- 4.6% (mean +/- SD) from serum and 92.8 +/- 5.4% from blood; within-day precision (n = 10) at 40 micrograms/l is 3.2% for serum and 4.2% for blood. Day-to-day precision at 40 micrograms/l (n = 10) was 4.5% for serum and 4.0% for blood. The detection limit is 0.7 microgram/l for serum and 1.0 microgram/l for blood. Blood samples have to be collected in glass tubes and stored at -20 degrees C.

D-penicillamine does not increase urinary bismuth excretion in patients treated with tripotassium dicitrato bismuthate

Twenty-four urinary bismuth excretion was measured in five patients who had been treated with tripotassium dicitrato bismuthate, before and after single 1 g oral dose of D-penicillamine. Before dosing with D-penicillamine, the median 24 h urinary bismuth output was 55 micrograms 24 h-1 (range 17-156 micrograms 24 h-1) and following dosing with D-penicillamine the median 24 h urinary bismuth output was 53 micrograms 24 h-1 (range 12-156 micrograms 24 h-1). D-penicillamine does not facilitate the urinary excretion of bismuth, hence it is unsuitable for use as an oral chelator in patients with bismuth intoxication.

The absorption of bismuth and salicylate from oral doses of Pepto-Bismol (bismuth salicylate)

Plasma bismuth and plasma salicylate concentrations were measured before and after three 30-ml oral doses of bismuth salicylate (Pepto-Bismol liquid) in 10 fasting healthy subjects. From 0 to 120 min following the first dose of bismuth salicylate, the plasma bismuth concentration was less than 1 ng/ml. The peak median plasma bismuth concentration was at +240 min (1.7 ng/ml; range 0.8-5.3 ng/ml). Salicylate appeared in the plasma of all subjects at +30 min, and it reached a peak at +120 min (median 61 mg/L; range 46-104 mg/L). The study demonstrates that, despite rapid and substantial absorption of salicylate, there is negligible absorption of bismuth into the bloodstream from standard oral doses of bismuth salicylate.

The safety and efficacy of tripotassium dicitrato bismuthate (De-Nol) maintenance therapy in patients with duodenal ulceration

Seventy-one patients whose duodenal ulcers had healed after a 4-week treatment period with tripotassium dicitrato bismuthate (TDB) were randomly allocated to receive maintenance treatment with either one TDB swallow tablet nocte (equivalent to 120 mg Bi2O3) or an identical placebo. During 12 months of follow-up, no side-effects were reported by TDB-treated patients, blood bismuth levels did not rise above discontinuation threshold concentrations (greater than 50 micrograms/L in the first 6 months, or greater than 100 micrograms/L in the second 6 months), and there were no adverse effects on haematological or biochemical indices. Ulcer relapse was significantly less in TDB-treated patients (P less than 0.025). Cumulative relapse rates at 6 and 12 months were 51% and 66%, respectively, for placebo-treated patients and 26% and 31%, respectively, for those who received TDB. It is likely that TDB is a safe and effective maintenance treatment for patients with duodenal ulcer disease.

Pharmacokinetics and toxicity of bismuth compounds

Inorganic bismuth salts are poorly soluble in water: solubility is influenced by the acidity of the medium and the presence of certain compounds with (hydr)oxy or sulfhydryl groups. The analysis of bismuth in biological material is not standardised and is subject to large variation; it is difficult to compare data from different studies, and older data should be approached with caution. The normal concentration of bismuth in blood is between 1 and 15 micrograms/L, but absorption from oral preparations produces a significant rise. Distribution of bismuth in the organs is largely independent of the compound administered or the route of administration: the concentration in kidney is always highest and the substance is also retained there for a long time. It is bound to a bismuth-metal binding protein in the kidney, the synthesis of which can be induced by the metal itself. Elimination from the body takes place by the urinary and faecal routes, but the exact proportion contributed by each route is still unknown. Elimination from blood displays multicompartment pharmacokinetics, the shortest half-life described in humans being 3.5 minutes, and the longest 17 to 22 years. A number of toxic effects have been attributed to bismuth compounds in humans: nephropathy, encephalopathy, osteoarthropathy, gingivitis, stomatitis and colitis. Whether hepatitis is a side effect, however, is open to dispute. Each of these adverse effects is associated with certain bismuth compounds. Bismuth encephalopathy occurred in France as an epidemic of toxicity and was associated with the intake of inorganic salts including bismuth subnitrate, subcarbonate and subgallate. In the prodromal phase patients developed problems in walking, standing or writing, deterioration of memory, changes in behaviour, insomnia and muscle cramps, together with several psychiatric symptoms. The manifest phase started abruptly and was characterised by changes in awareness, myoclonia, astasia and/or abasia and dysarthria. Patients recovered spontaneously after discontinuation of bismuth. Intestinal lavage, forced diuresis and haemodialysis have been tried without positive effects on the clinical condition of the patient or on blood bismuth concentration, and the use of dimercaprol as an antidote has produced reports of both positive and negative findings. To confirm the diagnosis of bismuth encephalopathy, it is essential to find elevated bismuth concentrations in blood, plasma, serum or CSF. A safety level of 50 micrograms/L and an alarm level of 100 micrograms/L have been suggested in the past, but no proof is available to support the choice of these levels.(ABSTRACT TRUNCATED AT 400 WORDS)

Bismuth accumulates in the body during treatment with tripotassium dicitrato bismuthate

Bismuth concentration was measured in plasma, dried leucocytes and urine in nine patients before, during and after treatment with tripotassium dicitrato bismuthate (De-Noltab 2 b.d.) for 6 weeks. During treatment there was an 8.5-fold rise in median plasma bismuth concentration (P less than 0.01), a non-significant doubling of leucocyte bismuth content, and a 349-fold rise in 24-h urinary bismuth excretion (P less than 0.01). The significantly increased urinary bismuth excretion continued for at least 3 months after cessation of treatment with tripotassium dicitrato bismuthate, indicating accumulation of bismuth during treatment with this drug.

The absorption of bismuth from oral doses of tripotassium dicitrato bismuthate

Two studies measured plasma concentrations of bismuth during dosing with tripotassium dicitrato bismuthate (De-Noltab). The first study compared 24 h plasma bismuth concentration and urinary bismuth excretion in six patients who had already received 29-131 days (median 47 days) of treatment with De-Noltab 2 b.d., and six healthy subjects who only received De-Noltab 2 b.d. on the day of study. There was a prompt rise in plasma bismuth concentration after each dose of De-Noltabs. The median 24 h integrated plasma bismuth concentration was similar in both groups, but the median 24 h urinary bismuth excretion was 5.4-fold higher in the patients. The second study compared the plasma bismuth concentrations after the first and third doses of De-Noltab 2 b.d. in 16 healthy subjects. The median peak bismuth concentration occurred 30 min (range 15-105 min) post-dosing. The peak plasma bismuth concentration was greater than 50 ng/ml in 14 of the 16 subjects, and greater than 100 ng/ml in nine of the subjects. There was no significant difference in the median integrated 10-h plasma bismuth concentration after the first or third dose of De-Noltabs. The results of these studies confirm that bismuth is absorbed and sequestrated during dosing with De-Noltabs. Bismuth is absorbed rapidly after oral dosing with De-Noltabs, to produce peak plasma bismuth concentrations hitherto considered to be in the range associated with bismuth neurotoxicity.

Non-ulcer dyspepsia and short term De-Nol therapy: a placebo controlled trial with particular reference to the role of Campylobacter pylori

This double blind randomised study tested the effectiveness of colloidal bismuth subcitrate (De-Nol) in non-ulcer dyspepsia (NUD) and if any benefit is associated with clearance of Campylobacter pylori (C pylori) from the gastric mucosa. Sixty six patients with dyspepsic symptoms, normal abdominal ultrasound, and upper GI endoscopy, were randomly allocated to placebo or De-Nol for eight weeks. Antral biopsies were taken for bacteriological and histological examination, and endoscopies and clinical questionnaires were administered before and after treatment. Fifty two patients (25 on De-Nol and 27 on placebo) completed the trial. De-Nol cleared C pylori from 10 of the 12 C pylori positive patients (83.3%), whereas placebo did not clear C pylori from any of the eight C pylori positive patients (p less than 0.01). In patients receiving De-Nol gastritis improved (p less than 0.01) and symptomatic response was better (p less than 0.001) compared with placebo. In the placebo group seven of the 19 C pylori negative patients became positive: this was associated with significant deterioration of symptoms, a phenomenon not seen in the De-Nol treated group.

Prevention of traveler's diarrhea by the tablet form of bismuth subsalicylate

In a randomized double-blind study, Swiss adults traveling to tropical countries for 12 to 28 days took a solid formulation of bismuth subsalicylate (1.05 or 2.1 g/day on a twice-daily regimen) or placebo. Efficacy was evaluated in 231 volunteers. Diarrheal incidence was reduced by 41% in persons taking the high dose (P = 0.007) and by 35% in those taking the low dose (P = 0.03) with excellent compliance. No serious adverse reactions occurred, but objectionable taste, constipation, and nausea were seen more frequently with active medication (P = 0.04). Twenty patients provided stool samples: no bacteria were detected in the 8 volunteers who were on active medication, but various bacteria were found in 5 of the 12 patients who had taken placebo (P = 0.04).

Uptake and subcellular localisation of bismuth in the gastrointestinal mucosa of rats after short term administration of colloidal bismuth subcitrate

Despite the topical action of colloidal bismuth subcitrate in promoting the healing of peptic ulcers, slight absorption of bismuth from the gastrointestinal tract has been reported in colloidal bismuth subcitrate-treated animals and man. The uptake and subcellular distribution of bismuth by the gastrointestinal tract of rats after 24 hours of colloidal bismuth subcitrate administration was studied. Mucosal uptake of bismuth (mean +/- SEM nmol/g protein) by gastric fundus (8.85 +/- 1.0) and antrum (7.23 +/- 1.50) was similar, but was significantly less than duodenum (19.2 +/- 3.7, p less than 0.05), jejunum (26.9 +/- 2.4, p less than 0.001) or ileum (22.4 +/- 2.2, p less than 0.001). Bismuth concentrations in antral and duodenal mucosae fell progressively over 72 hours to approximately 10% of initial concentrations (p less than 0.02). Subcellular fractionation studies of colloidal bismuth subcitrate treated duodenal enterocytes showed a brush border membrane and cytosolic localisation. These data suggest that some gastrointestinal mucosal uptake of bismuth occurs in colloidal bismuth subcitrate treated rats.

Tissue distribution of orally administered bismuth in the rat

1. A colloidal bismuth preparation, tripotassium dicitrato-bismuthate, was given (172 mg/kg body weight, 6/7 days) to 10 laboratory rats for 14 months. Bismuth was measured by atomic absorption spectrometry in various tissues and the pattern of distribution studied. 2. Bismuth was present in kidney lung, spleen, liver, brain, heart and skeletal muscles, in descending order of abundance. Haematological data, renal and liver function tests were normal in the bismuth-treated group. 3. The data suggested that chronic ingestion of bismuth in large doses in rats results in absorption and binding to tissues. Absorbed bismuth probably crosses the blood-brain barrier.