From the Guidelines
For patients with penicillin allergy who require Helicobacter pyli treatment, a PPI-clarithromycin-metronidazole combination is recommended as first-line in areas of low clarithromycin resistance, while bismuth-containing quadruple therapy is preferred in areas of high clarithromycin resistance. This approach is based on the Maastricht IV/Florence consensus report 1, which provides guidance on the management of H. pyli infection. The recommended first-line treatment in areas of low clarithromycin resistance consists of a proton pump inhibitor (PPI), clarithromycin, and metronidazole, while in areas of high clarithromycin resistance, a bismuth-containing quadruple therapy is recommended.
Some key points to consider when treating H. pyli infection in patients with penicillin allergy include:
- Confirming the penicillin allergy before proceeding with treatment, as many patients with reported penicillin allergies do not have true allergies
- Using a levofloxacin-containing regimen as a second-line alternative in areas of low fluoroquinolone resistance, which includes a PPI, levofloxacin, and clarithromycin
- Considering rifabutin as another candidate for treatment after two treatment failures, in addition to clarithromycin and levofloxacin
- Obtaining gastric biopsy specimens to culture H. pyli and perform susceptibility testing after two treatment failures, to guide the choice of antibiotics and minimize the risk of resistance.
The treatment regimens for H. pyli infection in patients with penicillin allergy are effective because they target the bacteria through different mechanisms, including disrupting bacterial cell membranes, inhibiting protein synthesis, damaging bacterial DNA, and inhibiting DNA gyrase. Treatment success should be confirmed with a urea breath test, stool antigen test, or biopsy-based testing at least 4 weeks after completion of therapy and after PPIs have been discontinued for at least 2 weeks, as recommended by the consensus report 1.