Successful eradication of Helicobacter pylori infection usually results in long-term remission of the ulcer because reinfection rates are low, particularly in areas of low endemicity. The organism is sensitive to metronidazole, amoxicillin, clarithromycin, tetracycline and bismuth salts, but eradication is difficult because of its location below the mucus layer. Numerous regimens have been proposed but none can offer more than 80-90% efficacy (see also Table 11.1). Therapy with one or two drugs is ineffective and current regimens comprise three or four drugs. The efficacy of antimicrobials can be increased considerably by mucosal protection with a proton pump inhibitor, ranitidine or bismuth citrate (in the latter case, in addition to its antimicrobial action). It is important that treatment be as short, simple and palatable as possible to encourage compliance, because failure to complete the course encourages antimicrobial resistance. Regimens containing bismuth compounds as the only mucosal protectant are less popular because they involve dosing four times daily and are unpalatable to some. Effective regimens include:
• Proton pump inhibitor or ranitidine bismuth citrate3 (as Ranitidine Bismutrex) b.d. + clarithromycin 500 mg b.d. + amoxycillin lg b.d. for 7 days.
• Proton pump inhibitor or ranitidine bismuth citrate b.d. + clarithromycin 500 mg b.d. + metronidazole 400 mg b.d. for 7 days.
Metronidazole resistance is a particular problem, with a prevalence of up to 80% in some countries, particularly sub-Saharan Africa. It probably reflects extensive use of this antimicrobial for pelvic and other infections, and is more common in women. Resistance to clarithromycin is less common but it may reach 10-15% of some communities.
It is not usually necessary to check for successful eradication unless the patient continues to have symptoms. Under these circumstances the urea breath test4 is a useful noninvasive technique.
3 A complex of ranitidine with bismuth and citrate from which ranitidine and bismuth are released.
NSAIDs AND THE STOMACH
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