[Lansoprazole: a review of its role in Helicobacter pylori eradication therapy]

Lansoprazole, a proton pump inhibitor with a potent gastric antisecretory effect, has a high in-vitro antimicrobial activity against H. pylori, although, used as monotherapy, achieves the true in vivo eradication in only a low proportion of patients. In spite of the fact that lansoprazole has a higher in vitro eradication efficacy than omeprazole, this does not imply a significative advantage in clinical practice when considering proton pump inhibitor plus amoxycillin combination, as both therapies have achieved discouraging results in Spain and in other countries. The addition of clarithromycin to lansoprazole is associated with variable results, which are better when lansoprazole is administered 30 mg b.i.d. (instead of 30 mg o.d.), however, the efficacy continues to be low. Thus, trying to improve therapeutic efficacy, two antibiotics have been added to lansoprazole, and this combination seems to be the ideal middle point where an excellent eradication efficacy is obtained, a low incidence of adverse effects, a high simplicity of the regimen, and a low cost. Combination of lansoprazole, clarithromycin and a nitroimidazole has, specifically, the advantage of allowing the use of low doses of lansoprazole (30 mg o.d.) and of claritrhomycin (250 mg b.i.d.) without losing therapeutic efficacy, and of being relatively effective even in patients with metronidazole-resistant strains. In the case of lansoprazole, amoxycillin and clarithromycin combination, the ideal posology of both lansoprazole and clarithromycin is still a matter of debate, but the dose of amoxycillin seems that it should be 1 g b. i.d. A theoric advantage of this regimen against that with nitroimidazoles is the lack of H. pylori penicillin resitance, while a disadvantage would be the possibility of allergies to this drug. Finally, the addition of a nitroimidazole to the lansoprazole and amoxycillin combination increases its eradication efficacy, especially in those patients with metronidazole-sensible strains; nevertheless, so that this combination can compete with other 'new' one-week triple therapies, its efficacy in short regimens (7 days) and at low doses (twice a day schemes) must be confirmed in future studies.