Archive for the ‘Gastroenterology’ Category


Ranitidine bismuth citrate: CONCLUSIONS

Apr 17, 2012 Author: Walter Mcneil | Filed under: Gastroenterology

CONCLUSIONS

In Canada, the approved dose of RBC is 400 mg twice daily with clarithromycin 250 mg four times daily (dual therapy) for two weeks for the treatment of patients with duodenal and gastric ulcer disease associated with H pylori infection. This may be followed by two weeks of RBC alone to facilitate ulcer healing. Adverse events are generally mild, treatment is well tolerated and bismuth toxicity is unlikely to arise. Studies to date of RBC triple therapy bid for one week show that when RBC is administered with clarithromycin and metronidazole or amoxicillin, eradication results are as effective as those achieved with the current first-line PPI-based triple therapy regimens. There is some suggestion that RBC combination treatments may overcome metronidazole resistance and possibly even clarithromycin resistance. Additionally, there appears to be a relatively low rate of acquired antibiotic resistance. Further data on the role of RBC combination therapies in antibiotic resistance and in the treatment of eradication failures are awaited with interest. Very cheap drugs at your disposal – cialis professional 20 mg to get best deals at best pharmacy.

In the Canadian H pylori Consensus Conference update, recommended therapies include a regimen of a PPI (omeprazole 20 mg, lansoprazole 30 mg or pantoprazole 400 mg) or RBC 400 mg, clarithromycin 500 mg and amoxicillin 1000 mg bid for seven days; or a regimen of a PPI or RBC, clarithromycin 500 mg or 250 mg, and metronidazole 500 mg bid for seven days.

Helicobacter pylori

Side effects and safety: Side effects reported with RBC are few and generally mild. Less than 1% of bismuth administered orally is absorbed systemically, and after repeated dosing with RBC 200 mg, 400 mg or 800 mg bid, trough bismuth concentrations do rise in a dose-dependent fashion in patients with and without renal impairment. However, levels remained below 50 pg/L, which is considered the upper limit of safety. Peak bismuth levels do not appear to rise as high as with tripotassium dicitrato bismuthate, another commonly used bismuth compound.

A randomized, double-blind, parallel group study compared the safety of RBC 400 mg bid with that of ranitidine 150 mg bid for up to one year. Adverse events were few and comparable between the two groups. Of patients treated with RBC, 29% reported drug-related adverse events, compared with 35% of those treated with ranitidine. Three per cent of RBC-treated patients experienced a serious event, compared with 2% of those treated with ranitidine. Trough plasma levels of bismuth increased slightly over time in patients treated with RBC. However, these levels returned to pretreatment values within three months after the end of treatment, and no patient had a plasma bismuth level of more than 50 ng/mL.

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Helicobacter pylori

RBC triple therapy in metronidazole- and clarithromycin-resistant Hpylori: Antibiotic resistance, particularly to metronidazole, can reduce the efficacy of Hpylori treatment regimens containing metronidazole. However, dual therapy with RBC and clarithromycin may be effective, with reported eradication in 11 of11 metronidazole-resistant H pylori strains. In this study, metronidazole resistance was defined as an MIC greater than 8 pg/mL by the E-test. In the same study, triple therapy with RBC, clarithromycin and metronidazole overcame metronidazole resistance in nine of 10 strains. Similar results were reported by Bardhan et al, who reported that triple therapy with RBC, clarithromycin 500 mg bid and metronidazole 400 mg bid for seven days successfully eradicated baseline metronidazole-resistant H pylori strains in nine of 10 patients.

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Helicobacter pylori

In vitro effects of RBC against H pylori: Resistant strains of H pylori are increasingly recognized. In vitro data have shown that RBC is effective in killing 14 different strains of H pylori. The MIC90 of RBC against H pylori is 15 pg/mL to 16 pg/mL. Both in vitro and in a mouse model, the combination of RBC with clarithromycin resulted in a synergistic increase in the activity against H pylori strains, even in those resistant to clarithromycin. Osato et al, demonstrated in 10 of 11 H pylori isolates that clarithromycin MIC90 values could be reduced by ninefold, on average, when combined with RBC, and still achieve microbial killing. Thus, RBC and clarithromycin acted syner-gistically to overcome resistance to clarithromycin. In another in vitro study, RBC showed synergy with clarithromycin and tetracycline against both sensitive and resistant strains of the bacterium. The mechanism of synergy remains unknown. RBC combined with metronidazole in vitro also demonstrated either total or partial synergy against metronidazole-resistant strains. Choose a perfect online pharmacy to get cialis professional and treat your health issue.

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Ranitidine bismuth citrate: RBC TRIPLE THERAPIES Part 4

Apr 10, 2012 Author: Walter Mcneil | Filed under: Gastroenterology

Helicobacter pylori

Other RBC triple combinations: Traditional bismuth, metronidazole and tetracycline (BMT) triple therapy was the best early treatment regimen for H pylori infections, and efficacy was enhanced by coadministration of an antisecre-tory drug. RBC combines two of these four components and simplifies administration of the drugs. In one four-arm study, RBC (either 400 mg bid or 200 mg qid) was given with either oxytetracycline 500 mg qid or spiramycin 500 mg qid and metronidazole 400 mg qid for 10 days. The ITT eradication rates ranged from 88.6% to 93.6%, and results were equivalent whether RBC was given two or four times daily and whether spiramycin or oxytetracycline was used. The authors suggested that spiramycin, which is less expensive than clarithromycin, deserves further study.

Triple therapy with RBC, metronidazole and tetracycline is less effective, and results are more variable, with an ITT eradication rate of 86% to 92% after seven days of therapy, 60% after 10 days of therapy, and 72% to 80% with 14 days of treatment. The best eradication rate was achieved in the studies that used the highest doses of metronidazole (1.5 g to 1.6 g daily) and tetracycline (500 mg qid) rather than smaller doses of metronidazole (250 mg tid to 500 mg bid) or tetracycline (500 mg bid or tid). Furthermore, baseline metronidazole resistance significantly (P=0.026) reduced eradication efficacy from 97% in patients with a metronidazole-sensitive strain to 57% in those with a resistant strain of H pylori. A Chinese study compared RBC or colloidal bismuth citrate with metronidazole and tetracycline triple therapy (RBC-metronidazole tetracycline [RBC-MT] compared with BMT) and reported contrasting results. The RBC-MT combination showed a trend toward a better eradication rate (46 of 50 patients, 92%) than with traditional BMT triple therapy (41 of 50 patients, 82%, P=0.23). Metronidazole resistance was defined as a minimal inhibitory concentration (MIC) greater than or equal to 32 mg/L using the E-test. In this study, 25 of 25 (100%) metronidazole-resistant strains were eradicated with the RBC-MT regimen, compared with 12 of 16 (75%, P=0.018) with traditional bismuth triple therapy. Reasons for the conflicting results between the different studies are unknown. Fast and reliable shopping for drugs – buy Ortho Tri-Cyclen birth control to get safe shopping atmosphere.

Treatment with RBC, tetracycline and clarithromycin for one to two weeks has been reported by two authors, with ITT eradication rates of over 90% in more than 100 patients.

One study compared RBC and amoxicillin for one week combined with azithromycin 500 mg od or 1 g od for three days. The higher dose of azithromycin was more successful, with ITT eradication in 27 of 36 patients (75%), compared with only 14 of 32 patients (44%) using the lower, 500 mg daily dose. The higher dose was associated with a trend toward more side effects, and two patients stopped treatment because of side effects, but the difference was not significant.

Ranitidine bismuth citrate: RBC TRIPLE THERAPIES Part 3

Apr 8, 2012 Author: Walter Mcneil | Filed under: Gastroenterology

RBC plus two antibiotics compared with PPI plus two antibiotics: RBC triple therapy has been compared with PPI triple therapy. Designs, dose, scheduling, testing details and ITT eradication rates from three studies are listed in Table 5. In all studies, there was no significant difference in eradication rates between the treatment groups. In one study, there was no difference between the RBC and the lansoprazole triple therapy arms, but because a low dose of lansoprazole (15 mg bid) was used, a difference may have been missed. Using either RBC or omeprazole with clarithromycin and amoxicillin, DU healing was similar and regimens were equally well-tolerated. This suggests that either RBC or a PPI triple combination can be used as first-line therapy; such a recommendation was made in a recent Canadian consensus update. Time to visit a trusted pharmacy – buy birth control online to begin your treatment now.

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Ranitidine bismuth citrate: RBC TRIPLE THERAPIES Part 2

Apr 7, 2012 Author: Walter Mcneil | Filed under: Gastroenterology

Eradication of H pylori with RBC plus clarithromycin and amoxicillin: Triple therapy with RBC, clarithromycin and amoxicillin omits metronidazole, possibly important in situations where infection with metronidazole-resistant strains of H pylori are suspected or documented. Table 4 shows the designs, dose, scheduling, testing details and ITT eradication rates from six studies. The dose of RBC in these trials was 400 mg bid for seven days in five of the six trials and for 14 days in one American study. The antibiotics were given for seven days; the dose of clarithromycin was usually 500 mg bid and amoxicillin was given as 1000 mg bid.

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Ranitidine bismuth citrate: RBC TRIPLE THERAPIES Part 1

Apr 6, 2012 Author: Walter Mcneil | Filed under: Gastroenterology

Eradication of H pylori with RBC plus clarithromycin and a nitroimidazole: The designs, doses, scheduling, testing details and ITT eradication rates from nine studies and 12 study arms of RBC in combination with clarithromycin and a ni-troimidazole (metronidazole or tinidazole) are shown in Table 3. The dose of RBC in these trials was 400 mg bid for seven to 14 days. No RBC was given after the end of the seven-day eradication regimens.

TABLE 3
Summary of triple therapy of ranitidine bismuth citrate (RBC) plus clarithromycin and a nitroimidazole (metronidazole or tinidazole)

Summary of triple therapy of ranitidine bismuth citrate

A Antrum; C Corpus; 13CUBT 13Carbon urea breath test; H Histology; ITT Intention-to-treat; RUT Rapid urease test 

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