Optimizing clarithromycin-containing therapy for Helicobacter pylori in the era of antibiotic resistance.

The efficacy of triple therapy for Helicobacter pylori infection has dramatically declined over the last decade, largely related to increasing clarithromycin resistance rates. From a microbiological standpoint, bismuth quadruple therapy is the ideal replacement since it combines drugs for which resistance does not impair its efficacy. Nonetheless, several obstacles such as availability, complexity or tolerance prevent a general implementation of bismuth quadruple therapy, so non-bismuth quadruple regimens remain the best first-line treatment in clinical practice in many geographical areas. We review the rationale and efficacy of several optimization tools (increasing the length of duration, high-dose acid suppression, probiotics), which have been largely evaluated over the last 5 years to increase the effectiveness of standard triple therapy. Then, we update available evidence on the effectiveness of several non-bismuth quadruple therapies (sequential, concomitant, hybrid, miscellaneous therapy), which have gained interest lately. We also revise evidence on the efficacy of the aforementioned optimization tools for non-bismuth quadruples schemes and, finally we provide a novel regionalized therapeutic algorithm, based on novel formulas recently developed for predicting the outcome of non-bismuth quadruple regimens, upon local antibiotic resistance rates.