Table 1.

Regimens for the treatment of Helicobacter pylori infection.

Treatment	Regimen	Duration	Recent First-Line Eradication Rate (ITT)	Recommendations According to Guidelines	Notes
Standard triple therapy (STT)	PPI standard dose bid Amoxicillin 1 g bid Clarithromycin 500 mg bid	7–14 d	63.9% [105], 74.1% [106]	First-line: optionally recommended by KCHUGR and JSHR Rescue: limited recommended by MAA	Over the past 20 years, the efficacy of STT has markedly decreased, and STT is generally not recommended as a first-line regimen
Bismuth quadruple therapy (BQT)	PPI standard dose bid Bismuth standard dose qid Metronidazole 500 mg tid Tetracycline 500 mg qid	7–14 d	82.8% [107], 88.2% [44], 91.5% [108]	First-line: recommended by ACG, MAA, TOR, and KCHUGR (optionally) Rescue: recommended by ACG, MAA, TOR, and KCHUGR	BQT has been suggested as a first-line treatment option in many guidelines, especially for regions with a high clarithromycin resistance.
Concomitant therapy (non-bismuth quadruple therapy)	PPI standard dose bid Clarithromycin 500 mg bid Amoxicillin 1g bid Metronidazole 500 mg bid	10–14 d	84.6% [106], 90.1% [109], 93.5% [110]	First-line: recommended by ACG, MAA, and TOR Rescue: recommended by ACG and MAA	The eradication rate is superior to that of CTT, and the method of administration is simple compared to that of sequential therapy. But, adverse events may be more likely with concomitant therapy.
Sequential therapy	PPI standard dose bid Amoxicillin 1g bid (first half only) Clarithromycin 500 mg bid (for the second half only) Metronidazole 500 mg bid (for the second half only)	10–14 d	69.5% [106], 82.0% [111], 87.0% [112]	First-line: optionally recommended (not ideal) by ACG Rescue: not recommended in all guidelines	As first-line therapy, the role is gradually disappearing. It is a cumbersome way to reduce patient compliance.
Hybrid therapy	PPI standard dose bid Amoxicillin 1g bid Clarithromycin 500 mg bid (for the second half only) Metronidazole 500 mg bid (for the second half only)	14 d	85.8 % [75], 92.8% [113]	First-line: optionally recommended (not ideal) by ACG Rescue: not recommended in all guidelines	It is a method that combines sequential therapy and concomitant therapy.
Levofloxacin-based therapy	Levofloxacin can be given as triple therapy or quadruple therapy.	10–14 d	85.5% [76], 94.0% [77]	First-line: recommended by ACG Rescue: recommended by ACG, MAA, and TOR	Most guidelines recommend that levofloxacin-based therapy be applied as rescue therapy rather than first-line. It is less effective for areas with high quinolone resistance.
Rifabutin-based therapy	PPI standard dose bid Amoxicillin 1g bid Rifabutin 150 mg bid	10 d	83.8% [93]	First-line: not recommended in all guidelines Rescue: optionally recommended (third or fourth-line) by MAA and TOR	All guidelines recommend rifabutin-based therapy as rescue therapy. Rifabutin has the rare risk of myelotoxicity; therefore, careful use is required.
Potassium-competitive acid blocker based therapy	P-CAB can be given as triple therapy or quadruple therapy by replacing PPI with P-CAB.	7–14 d	89.2% [104], 90.2% [114]	Not stated in algorithm of guidelines	The role of potent acid suppression is expected to increase gradually, and more research is needed.
H. pylori treatment based on antibacterial susceptibility test	Tailored therapy according to AST results	7–14 d	92.7% [31], 92.9% [115]	MAA recommends to perform AST after the failure of second-line treatment.	The results of tailored therapy based on AST are excellent, and it is expected to play a role in improving H. pylori treatment in the future. Efforts to facilitate the application of AST in clinical practice are required.

ITT, intention to treat; STT, standard triple therapy; PPI, proton pump inhibitor; KCHUGR, Korean College of Helicobacter and Upper Gastrointestinal Research [116]; JSHR, Japanese Society for Helicobacter Research [117]; MAA, Maastricht V/Florence Consensus [10]; BQT, bismuth quadruple therapy; ACG, American College of Gastroenterology clinical guideline [4]; TOR, Toronto Consensus [9]; CTT, concomitant therapy; P-CAB, potassium-competitive acid blocker; AST, antimicrobial susceptibility test.