Comparative study of allicin-containing quadruple therapy vs. bismuth-containing quadruple therapy for the treatment of Helicobacter pylori infection: a prospective randomized study

Bismuth has antimicrobial activity and can improve the efficacy of triple Helicobacter pylori (H. pylori) therapy. Allicin added to conventional therapy for H. pylori infection also improves H. pylori eradication rates. Thus, this study aims to evaluate and compare the efficacy, safety and tolerability of allicin-containing quadruple therapy and bismuth-containing quadruple therapy and to investigate the factors that affect the eradication rates.Two hundred twenty H. pylori-infected patients were included and randomly (1:1) assigned to 14-day quadruple therapy: ilaprazole (5 mg bid), doxycycline (100 mg bid), and furazolidone (100 mg bid) with an allicin soft capsule (40 mg of DATS tid) (IDFA) or colloidal bismuth tartrate (220 mg of elemental bismuth bid) (IDFB). Eradication was confirmed by urea breath tests. Symptom improvement, adverse events, and adherence were assessed by a questionnaire.In the intention-to-treat and per-protocol analysis, the eradication rates for IDFA and IDFB groups were 87.5% (70/80) vs. 86.3% (69/80, P = 0.815) and 91.9% (68/74) vs. 91.8% (67/73, P = 0.980) as first-line therapies; 83.3% (25/30) vs. 83.3% (25/30, P = 1) and 89.3% (25/28) vs. 88.9% (24/27, P = 1) as second-line therapies. Symptom improvement rates were 96.1% and 97.0% for IDFA and IDFB (P = 1). The adverse event rates were 10.9% in IDFA and 14.5% in IDFB groups (P = 0.418). Nausea occurred frequently in IDFB than IDFA (1.8% vs. 8.2%, P = 0.030). Smoking and sharing utensils significantly affected the efficacy.Allicin-containing quadruple therapy might be regarded as a promising alternative to bismuth-containing quadruple therapy in H. pylori eradication.